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Cold sores, also called fever blisters, can show up anywhere on your body. They're most likely to appear on the outside of your mouth and lips, but you can also find them on your nose, cheeks, or fingers.

After the blisters form, you may notice that they break and ooze. A yellow crust or a scab builds up and eventually falls off, revealing new skin underneath.

The sores usually last 7 to 10 days and can spread to other people until they crust over completely.

Whipple disease is a rare bacterial infection that most often affects your gastrointestinal system. Whipple disease interferes with normal digestion by impairing the breakdown of foods, such as fats and carbohydrates, and hampering your body's ability to absorb nutrients.Whipple disease also can infect other organs, including your brain, heart, joints and eyes.Without proper treatment, Whipple disease can be serious or fatal. However, a course of antibiotics can treat Whipple disease

White blood cells (leukocytes) orchestrate the host response to pathogens. Leukocytes are divided into myeloid (eosinophils, monocytes, neutrophils, basophils) and lymphoid (B cells, T cells, and natural killer (NK) cells) elements. Monocytes and neutrophils mediate innate immune defenses and present antigens to lymphocytes, the principal effectors of the adaptive immune system. Eosinophils and basophils defend against parasitic pathogens, play important roles in inflammation, and mediate allergic reactions.Monocytes and neutrophils, as part of innate immunity, phagocytose bacteria and debris, eliminate virus-infected cells, and destroy parasites and fungi. Phagocytosis is assisted by serum complement proteins, which adhere to pathogens and promote chemotaxis and opsonization. Monocytes mature in tissue to become macrophages, where they, along with dendritic cells and B cells, serve as antigen presenting cells (APCs) to the adaptive immune system.B and T cells, as part of adaptive immunity, confer long-term protection against pathogens, especially extracellular bacterial infections. Adaptive immunity orchestrates both antibody-mediated humoral immunity and T-cell mediated cellular cytotoxicity. B cells secrete neutralizing antigen-specific antibodies (i.e. humoral) upon stimulation by the macrophages, dendritic cells, and T cells. In contrast, T cells and NK cells, upon stimulation, can directly kill aberrant cells (i.e. cell-mediated). These aberrant cells include those infected with viruses, bacteria, and fungi, tumorigenic cells, and transplanted tissue.

Wilson's disease is a rare inherited disorder that causes copper to accumulate in your liver, brain and other vital organs. Most people with Wilson's disease are diagnosed between the ages of 5 and 35, but it can affect younger and older people, as well.Copper plays a key role in the development of healthy nerves, bones, collagen and the skin pigment melanin. Normally, copper is absorbed from your food, and excess is excreted through a substance produced in your liver (bile).But in people with Wilson's disease, copper isn't eliminated properly and instead accumulates, possibly to a life-threatening level. When diagnosed early, Wilson's disease is treatable, and many people with the disorder live normal lives.

Most adults have 32 teeth, including 4 wisdom teeth that usually emerge between the ages of 17 and 21.

This final set of molars can play a useful part in the mouth for many people.

However, for others, if they don’t come through properly or don’t emerge at all, they may need to be removed.

Having wisdom teeth out is one of the most common dental procedures in the UK.

Wisdom Teeth

Wisdom teeth present potential problems when they are misaligned as they can position themselves horizontally, be angled toward or away from the second molars or be angled inward or outward. Poor alignment of wisdom teeth can crowd or damage adjacent teeth, the jawbone, and nerves. Wisdom teeth that lean toward the second molars make those teeth more vulnerable to decay by entrapping plaque and debris.

In addition, wisdom teeth can be entrapped completely within the soft tissue and/or the jawbone or only partially break through, or erupt, through the gum.

Teeth that remain partially or completely entrapped within the soft tissue or the jawbone are called impacted. Wisdom teeth that only partially erupt allow an opening for bacteria to enter around the tooth and cause an infection, which results in pain, swelling, jaw stiffness, and general illness. Partially erupted teeth are also more prone to tooth decay and gum disease because their hard-to-reach location and awkward positioning makes brushing and flossing difficult.

In Wolff-Parkinson-White (WPW) syndrome, an extra electrical pathway between your heart's upper and lower chambers causes a rapid heartbeat. The extra pathway is present at birth and fairly rare.The episodes of fast heartbeats usually aren't life-threatening, but serious heart problems can occur. Treatment can stop or prevent episodes of fast heartbeats. A catheter-based procedure (ablation) can permanently correct the heart rhythm problems.Most people with an extra electrical pathway experience no fast heartbeat. This condition, called Wolff-Parkinson-White pattern, is discovered only by chance during a heart exam. Although WPW pattern is often harmless, doctors might recommend further evaluation before children with WPW pattern participate in high-intensity sports.

A wrist fracture is a medical term for a broken wrist. The wrist is made up of eight small bones which connect with the two long forearm bones called the radius and ulna. Although a broken wrist can happen in any of these 10 bones, by far the most common bone to break is the radius. This is called a distal radius fracture by hand surgeons (Figure 1).Some wrist fractures are stable. “Non-displaced” breaks, in which the bones do not move out of place initially, can be stable. Some “displaced” breaks (which need to be put back into the right place, called “reduction” or “setting”) also can be stable enough to treat in a cast or splint. Other fractures are unstable. In unstable fractures, even if the bones are put back into position and a cast is placed, the bone pieces tend to move or shift into a bad position before they solidly heal. This can make the wrist appear crooked.Some fractures are more severe than others. Fractures that break apart the smooth joint surface or fractures that shatter into many pieces (comminuted fractures) may make the bone unstable. These severe types of fractures often require surgery to restore and hold their alignment. An open fracture occurs when a fragment of bone breaks and is forced out through the skin. This can cause an increased risk of infection in the bone.

Colic is uncontrollable crying in an otherwise healthy baby. Your baby is considered colicky if he’s younger than 5 months old and cries for more than three hours in a row on three or more days a week for at least three weeks (phew!). Colic isn't a disease and won't cause your baby any long-term harm, but it's a tough thing to go through for babies and their parents.

If your baby is colicky, find more than 20 sanity-saving tips to help you deal with it in our article about coping with colic.

X-linked agammaglobulinemia (XLA) is a condition that affects the immune system and occurs almost exclusively in males. People with XLA have very few B cells, which are specialized white blood cells that help protect the body against infection. B cells can mature into the cells that produce special proteins called antibodies or immunoglobulins. Antibodies attach to specific foreign particles and germs, marking them for destruction. Individuals with XLA are more susceptible to infections because their body makes very few antibodies.Children with XLA are usually healthy for the first 1 or 2 months of life because they are protected by antibodies acquired before birth from their mother. After this time, the maternal antibodies are cleared from the body, and the affected child begins to develop recurrent infections. In children with XLA, infections generally take longer to get better and then they come back again, even with antibiotic medications. The most common bacterial infections that occur in people with XLA are lung infections (pneumonia and bronchitis), ear infections (otitis), pink eye (conjunctivitis), and sinus infections (sinusitis). Infections that cause chronic diarrhea are also common. Recurrent infections can lead to organ damage. People with XLA can develop severe, life-threatening bacterial infections; however, affected individuals are not particularly vulnerable to infections caused by viruses. With treatment to replace antibodies, infections can usually be prevented, improving the quality of life for people with XLA.

Triple X syndrome, also called trisomy X, is a genetic disorder that affects about 1 in 1,000 females. Females normally have two X chromosomes in all cells — one X chromosome from each parent. In triple X syndrome, a female has three X chromosomes.Many girls and women with triple X syndrome have no symptoms or only mild symptoms. In other cases, symptoms may be more pronounced — possibly including developmental delays and learning disabilities.Treatment for triple X syndrome depends on which symptoms, if any, are present and their severity. Normal sexual development and the ability to have children are typical for most females who have triple X syndrome.

Yellow fever virus is found in tropical and subtropical areas in South America and Africa. The virus is transmitted to people by the bite of an infected mosquito. Yellow fever is a very rare cause of illness in U.S. travelers. Illness ranges in severity from a self-limited febrile illness to severe liver disease with bleeding. Yellow fever disease is diagnosed based on symptoms, physical findings, laboratory testing, and travel history, including the possibility of exposure to infected mosquitoes. There is no specific treatment for yellow fever; care is based on symptoms. Steps to prevent yellow fever virus infection include using insect repellent, wearing protective clothing, and getting vaccinated.

Plague is a serious bacterial infection that's transmitted by fleas. Known as the Black Death during medieval times, today plague occurs in fewer than 5,000 people a year worldwide. It can be deadly if not treated promptly with antibiotics.The organism that causes plague, Yersinia pestis, lives in small rodents found most commonly in rural and semirural areas of Africa, Asia and the United States. The organism is transmitted to humans who are bitten by fleas that have fed on infected rodents or by humans handling infected animals.The most common form of plague results in swollen and tender lymph nodes — called buboes — in the groin, armpits or neck. The rarest and deadliest form of plague affects the lungs, and it can be spread from person to person.

Zika (Zee-ka) virus disease is a mosquito-borne viral infection that primarily occurs in tropical and subtropical areas of the world. Most people infected with Zika virus have no signs and symptoms, while others report mild fever, rash and muscle pain. Other signs and symptoms may include headache, red eyes (conjunctivitis) and a general feeling of discomfort.

Zika virus infections during pregnancy have been linked to miscarriage and can cause microcephaly, a potentially fatal congenital brain condition. Zika virus also may cause other neurological disorders such as Guillain-Barre syndrome.

Researchers are working on a Zika virus vaccine. For now the best prevention is to prevent mosquito bites and reduce mosquito habitats.

Zollinger-Ellison syndrome is a rare condition in which one or more tumors form in your pancreas or the upper part of your small intestine (duodenum). These tumors, called gastrinomas, secrete large amounts of the hormone gastrin, which causes your stomach to produce too much acid. The excess acid then leads to peptic ulcers, as well as to diarrhea and other symptoms.

Zollinger-Ellison syndrome (ZES) is rare. The disease may occur at any time in life, but people are usually diagnosed between ages 20 and 50. Medications to reduce stomach acid and heal the ulcers is the usual treatment for Zollinger-Ellison syndrome.

Shingles, also known as herpes zoster, is a viral disease characterized by a painful skin rash with blisters in a localized area.

Shingles is an infection caused by the varicella-zoster virus, which is the same virus that causes chickenpox. Even after the chickenpox infection is over, the virus may live in your nervous system for years before reactivating as shingles. Shingles may also be referred to as herpes zoster.

This type of viral infection is characterized by a red skin rash that can cause pain and burning. Shingles usually appears as a stripe of blisters on one side of the body, typically on the torso, neck, or face.

Most cases of shingles clear up within two to three weeks. Shingles rarely occurs more than once in the same person, but approximately 1 in 3 people in the United States will have shingles at some point in their life, according to the Centers for Disease Control and Prevention.

Dissociative disorders are mental disorders that involve experiencing a disconnection and lack of continuity between thoughts, memories, surroundings, actions and identity. People with dissociative disorders escape reality in ways that are involuntary and unhealthy and cause problems with functioning in everyday life.

Dissociative disorders usually develop as a reaction to trauma and help keep difficult memories at bay. Symptoms — ranging from amnesia to alternate identities — depend in part on the type of dissociative disorder you have. Times of stress can temporarily worsen symptoms, making them more obvious.

Treatment for dissociative disorders may include talk therapy (psychotherapy) and medication. Although treating dissociative disorders can be difficult, many people learn new ways of coping and lead healthy, productive lives.

Colon cleansing (also known as colon therapy) encompasses a number of alternative medical therapies claimed to remove nonspecific toxins from the colon and intestinal tract by removing any accumulations of feces. Colon cleansing may be branded colon hydrotherapy, a colonic or colonic irrigation. During the 2000s internet marketing and infomercials of oral supplements supposedly for colon cleansing increased.

Some forms of colon hydrotherapy use tubes to inject water, sometimes mixed with herbs or with other liquids, into the colon via the rectum using special equipment. Oral cleaning regimens use dietary fiber, herbs, dietary supplements, or laxatives. People who practice colon cleansing believe that accumulations of putrefied feces line the walls of the large intestine and that these accumulations harbor parasites or pathogenic gut flora, causing nonspecific symptoms and general ill-health. This "auto-intoxication" hypothesis is based on medical beliefs of the Ancient Egyptians and Greeks and was discredited in the early 20th century.

A double uterus is a rare congenital abnormality. In a female fetus, the uterus starts out as two small tubes. As the fetus develops, the tubes normally join to create one larger, hollow organ — the uterus.

Sometimes, however, the tubes don't join completely. Instead, each one develops into a separate structure. A double uterus may have one opening (cervix) into one vagina, or each uterine cavity may have a cervix. In many cases, a thin wall of tissue runs down the length of the vagina, dividing it into two separate openings.

Women who have a double uterus often have successful pregnancies. But the condition can increase the risk of miscarriage or premature birth.

A drug allergy is the abnormal reaction of your immune system to a medication. Any medication — over-the-counter, prescription or herbal — is capable of inducing a drug allergy. However, a drug allergy is more likely with certain medications.

The most common signs and symptoms of drug allergy are hives, rash or fever. A drug allergy may cause serious reactions, including a life-threatening condition that affects multiple body systems (anaphylaxis).

A drug allergy is not the same as a drug side effect, a known possible reaction listed on a drug label. A drug allergy is also different from drug toxicity caused by an overdose of medication.

Dry eyes is a common condition that occurs when your tears aren't able to provide adequate lubrication for your eyes. Tears can be inadequate for many reasons. For example, dry eyes may occur if you don't produce enough tears or if you produce poor-quality tears.

Dry eyes feel uncomfortable. If you have dry eyes, your eyes may sting or burn. You may experience dry eyes in certain situations, such as on an airplane, in an air-conditioned room, while riding a bike or after looking at a computer screen for a few hours.

Treatments for dry eyes may make you more comfortable. These treatments can include lifestyle changes and eyedrops. You'll likely need to take these measures indefinitely to control the symptoms of dry eyes.

The typical scenario for dry socket is the occurrence of throbbing pain about two to four days after the tooth is extracted. Dry socket pain is often accompanied by bad breath and a foul taste in the mouth. With this onset of pain, it is obvious that proper healing has been interrupted.

Dry socket is a condition in which there is inflammation of the jawbone (or alveolar bone) after a tooth extraction. It is also referred to as "alveolar osteitis" and is one of the many complications that can occur from a tooth extraction. The occurrence of dry socket is relatively rare, occurring in about 2% of tooth extractions. However, that percentage rises to at least 20% when it involves the removal of mandibular impacted third molars (lower wisdom teeth).

Dumping syndrome is a condition that can develop after surgery to remove all or part of your stomach or after surgery to bypass your stomach to help you lose weight. Also called rapid gastric emptying, dumping syndrome occurs when food, especially sugar, moves from your stomach into your small bowel too quickly.

Most people with dumping syndrome develop signs and symptoms, such as abdominal cramps and diarrhea, 10 to 30 minutes after eating. Other people have symptoms one to three hours after eating, and still others have both early and late symptoms.

Generally, you can help prevent dumping syndrome by changing your diet after surgery. Changes might include eating smaller meals and limiting high-sugar foods. In more-serious cases of dumping syndrome, you may need medications or surgery.

Dust mite allergy is an allergic reaction to tiny bugs that commonly live in house dust. Signs of dust mite allergy include those common to hay fever, such as sneezing and runny nose. Many people with dust mite allergy also experience signs of asthma, such as wheezing and difficulty breathing.

Dust mites, close relatives of ticks and spiders, are too small to see without a microscope. Dust mites eat skin cells shed by people, and they thrive in warm, humid environments. In most homes, such items as bedding, upholstered furniture and carpeting provide an ideal environment for dust mites.

By taking steps to reduce the number of dust mites in your home, you may get control of dust mite allergy. Medications or other treatments are sometimes necessary to relieve symptoms and manage asthma.

Earwax blockage occurs when earwax (cerumen) accumulates in your ear or becomes too hard to wash away naturally.

Earwax is a helpful and natural part of your body's defenses. It cleans, lubricates and protects your ear canal by trapping dirt and slowing the growth of bacteria.

If earwax blockage becomes a problem, you or your doctor can take simple steps to remove the wax safely.

Eating disorders are serious conditions related to persistent eating behaviors that negatively impact your health, your emotions and your ability to function in important areas of life. The most common eating disorders are anorexia nervosa, bulimia nervosa and binge-eating disorder.

Most eating disorders involve focusing too much on your weight, body shape and food, leading to dangerous eating behaviors. These behaviors can significantly impact your body's ability to get adequate nutrition. Eating disorders can harm the heart, digestive system, bones, and teeth and mouth, and lead to other diseases.

Eating disorders often develop in the teen and young adult years, although they can develop at other ages. With treatment, you can return to healthier eating habits and sometimes reverse serious complications caused by the eating disorder.

An ectopic pregnancy is an early pregnancy that occurs outside of the normal location (uterine lining) for a developing pregnancy. Most ectopic pregnancies occur in the Fallopian tubes. An ectopic pregnancy cannot progress normally and typically results in the death of the embryo or fetus.

Ectropion (ek-TROH-pee-on) is a condition in which your eyelid turns outward. This leaves the inner eyelid surface exposed and prone to irritation.

Ectropion is more common in older adults, and it generally affects only the lower eyelid. In severe ectropion, the entire length of the eyelid is turned out. In less severe ectropion, only one segment of the eyelid sags away from the eye.

Artificial tears and lubricating ointments can help relieve symptoms of ectropion. But usually surgery is needed to fully correct the condition.

Eggs are one of the most common allergy-causing foods for children.

Egg allergy symptoms usually occur a few minutes to a few hours after eating eggs or foods containing eggs. Signs and symptoms range from mild to severe and can include skin rashes, hives, nasal congestion, and vomiting or other digestive problems. Rarely, egg allergy can cause anaphylaxis — a life-threatening reaction.

Egg allergy can occur as early as infancy. Most children, but not all, outgrow their egg allergy before adolescence.

Ehrlichiosis is a bacterial illness transmitted by ticks that causes flu-like symptoms. The signs and symptoms of ehrlichiosis range from mild body aches to severe fever and usually appear within a week or two of a tick bite. If treated quickly with appropriate antibiotics, ehrlichiosis generally improves within a few days.

Another tick-borne infection — anaplasmosis — is closely related to ehrlichiosis. But the two have distinct differences and are caused by different microorganisms.

The best way to prevent these infections is to avoid tick bites. Tick repellents, thorough body checks after being outside and proper removal of ticks give you the best chance of avoiding ehrlichiosis.

Eisenmenger (I-sun-meng-uhr) syndrome is a complication of a heart defect that you're born with (congenital).

A heart defect that causes a hole (shunt) to develop between two chambers of your heart is the most common cause of Eisenmenger syndrome. This hole causes blood to circulate abnormally in your heart and lungs. Increased blood flow returns to your lungs instead of going to the rest of your body. The blood vessels in your lung arteries become stiff and narrow, increasing the pressure in your lungs' arteries. This permanently damages the blood vessels in your lungs.

Eisenmenger syndrome occurs when the increased pressure of the blood flow in the lung becomes so great that the direction of blood flow through the shunt reverses. Oxygen-poor (blue) blood from the right side of the heart flows into the left ventricle and is pumped to your body so you don't receive enough oxygen to all your organs and tissues.

Eisenmenger syndrome is a life-threatening condition requiring careful medical monitoring. Medications can improve symptoms and prognosis.

 Central nervous system (CNS) embryonal tumors form in embryonic cells that remain in the brain after birth. CNS embryonal tumors tend to spread through the cerebrospinal fluid (CSF) to other parts of the brain and spinal cord.

The tumors may be malignant (cancer) or benign (not cancer). Most CNS embryonal tumors in children are malignant. Malignant brain tumors are likely to grow quickly and spread into other parts of the brain. When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Benign brain tumors grow and press on nearby areas of the brain. They rarely spread to other parts of the brain. Both benign and malignant brain tumors can cause signs or symptoms and need treatment.

Although cancer is rare in children, brain tumors are the third most common type of childhood cancer, after leukemia and lymphoma. This summary is about the treatment of primary brain tumors (tumors that begin in the brain). The treatment of metastatic brain tumors, which begin in other parts of the body and spread to the brain, is not discussed in this summary. For information about the different types of brain and spinal cord tumors, see the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview.

Brain tumors occur in both children and adults. Treatment for adults may be different from treatment for children. See the PDQ summary on Adult Central Nervous System Tumors Treatment for more information on the treatment of adults.

Encopresis (en-ko-PREE-sis), sometimes called fecal incontinence or soiling, is the repeated passing of stool (usually involuntarily) into clothing. Typically it happens when impacted stool collects in the colon and rectum: the colon becomes too full and liquid stool leaks around the retained stool, staining underwear. Eventually, stool retention can cause swelling (distention) of the bowels and loss of control over bowel movements.

Encopresis usually occurs after age 4, when the child has already learned to use a toilet. In most cases, soiling is a symptom of chronic constipation. Far less frequently it occurs without constipation and may be the result of emotional issues.

Encopresis can be frustrating for parents — and embarrassing for the child. However, with patience and positive reinforcement, treatment for encopresis is usually successful

Some couples are almost desperate to conceive a baby of one particular gender. Fathers especially, can be eager to have a boy but there are also mothers who long for a son. Most couples however, are happy with either a boy or a girl baby, as long as it is healthy and strong. But if you are keen to try to sway the odds of having a boy then there is no harm in trying. Just remember that there are no guarantees and the odds of conceiving a boy or a girl are almost exactly the same for each and every pregnancy.

Endocarditis generally occurs when bacteria, fungi or other germs from another part of your body, such as your mouth, spread through your bloodstream and attach to damaged areas in your heart. If it's not treated quickly, endocarditis can damage or destroy your heart valves and can lead to life-threatening complications. Treatments for endocarditis include antibiotics and, in certain cases, surgery.

Since there are many ways to develop endocarditis, your doctor might not be able to pinpoint the exact cause of your condition. However, people at greatest risk of endocarditis usually have damaged heart valves, artificial heart valves or other heart defects.

Endometrial cancer is a type of cancer that begins in the uterus. The uterus is the hollow, pear-shaped pelvic organ in women where fetal development occurs.

Endometrial cancer begins in the layer of cells that form the lining (endometrium) of the uterus. Endometrial cancer is sometimes called uterine cancer. Other types of cancer can form in the uterus, including uterine sarcoma, but they are much less common than endometrial cancer.

Endometrial cancer is often detected at an early stage because it frequently produces abnormal vaginal bleeding, which prompts women to see their doctors. If endometrial cancer is discovered early, removing the uterus surgically often cures endometrial cancer.

An enlarged heart (cardiomegaly) isn't a disease, but rather a sign of another condition.

The term "cardiomegaly" refers to an enlarged heart seen on any imaging test, including a chest X-ray. Other tests are then needed to diagnose the condition causing your enlarged heart.

You may develop an enlarged heart temporarily because of a stress on your body, such as pregnancy, or because of a medical condition, such as the weakening of the heart muscle, coronary artery disease, heart valve problems or abnormal heart rhythms.

Certain conditions may cause the heart muscle to thicken or one of the chambers of the heart to dilate, making the heart larger. Depending on the condition, an enlarged heart may be temporary or permanent.

An enlarged heart may be treatable by correcting the cause. Treatment for an enlarged heart can include medications, medical procedures or surgery.

If your doctor tells you that you've got an enlarged liver, it means it's swollen beyond its normal size. There's usually another condition that's causing it, such as hepatitis. You have a lot of treatment choices, but you first need to find out the source of the problem.

Getting treated is important. Your liver has a lot of big jobs to do. Just to name a few key ones, it helps clean your blood by getting rid of harmful chemicals that your body makes. It makes a liquid called bile, which helps you break down fat from food. And it also stores sugar, called glucose, which gives you a quick back-up energy boost when you need it.

Depending on what's causing your liver to swell, you could end up with long-term damage if you don't get treated.

Entropion (en-TROH-pee-on) is a condition in which your eyelid turns inward so that your eyelashes and skin rub against the eye surface. This causes irritation and discomfort.

When you have entropion, your eyelid may be turned in all the time or only when you blink hard or squeeze your eyelids shut. Entropion is more common in older adults, and it generally affects only the lower eyelid.

Artificial tears and lubricating ointments can help relieve symptoms of entropion. But usually surgery is needed to fully correct the condition. Left untreated, entropion can cause damage to the transparent covering in the front part of your eye (cornea), eye infections and vision loss.

In eosinophilic esophagitis (e-o-sin-o-FILL-ik uh-sof-uh-JIE-tis), a type of white blood cell (eosinophil) builds up in the lining of the tube that connects your mouth to your stomach (esophagus). This buildup, which is a reaction to foods, allergens or acid reflux, can inflame or injure the esophageal tissue. Damaged esophageal tissue can lead to difficulty swallowing or cause food to get stuck when you swallow.

Eosinophilic esophagitis is a chronic immune system disease. It has been identified only in the past two decades, but is now considered a major cause of digestive system (gastrointestinal) illness. Research is ongoing and will likely lead to revisions in the diagnosis and treatment of eosinophilic esophagitis.

If you learn that you or your child has a type of spine and brain cancer called an ependymoma, there's a lot to take in. You'll have lots of questions about how to treat the disease and manage the swirl of emotions you may feel.

Depending on where the cancer is, your doctor may recommend surgery, chemotherapy, or radiation. But make sure you take care of your mental health, too. Turn to family, friends, and support groups to get the emotional backing you need.

Epidermoid (ep-ih-DUR-moid) cysts are noncancerous small bumps beneath the skin. They can appear anywhere on the skin, but are most common on the face, neck and trunk.

Epidermoid cysts are slow growing and often painless, so they rarely cause problems or need treatment. You might choose to have a cyst removed by a doctor if its appearance bothers you or if it's painful, ruptured or infected.

Many people refer to epidermoid cysts as sebaceous cysts, but they're different. True sebaceous cysts are less common. They arise from the glands that secrete oily matter that lubricates hair and skin (sebaceous glands).

Epidermolysis bullosa (ep-ih-dur-MOL-uh-sis buhl-LOE-sah) is a group of rare diseases that cause fragile, blistering skin. The blisters may appear in response to minor injury, even from heat, rubbing, scratching or adhesive tape. In severe cases, the blisters may occur inside the body, such as the lining of the mouth or the stomach.

Most types of epidermolysis bullosa are inherited. The condition usually shows up in infancy or early childhood. Some people don't develop signs and symptoms until adolescence or early adulthood.

Epidermolysis bullosa has no cure, though mild forms may improve with age. Treatment focuses on caring for blisters and preventing new ones.

Epididymitis (ep-ih-did-uh-MY-tis) is an inflammation of the coiled tube (epididymis) at the back of the testicle that stores and carries sperm. Males of any age can get epididymitis.

Epididymitis is most often caused by a bacterial infection, including sexually transmitted infections (STIs), such as gonorrhea or chlamydia. Sometimes, a testicle also becomes inflamed — a condition called epididymo-orchitis.

Congestive Heart Failure (Heart Failure) – Pipeline Review, H2 2017, provides an overview of the Congestive Heart Failure (Heart Failure) (Cardiovascular) pipeline landscape.

Heart failure is also known as congestive heart failure (CHF). CHF is a condition in which the heart is no longer able to pump out enough oxygen-rich blood. Symptoms include cough, fatigue, weakness, faintness, loss of appetite, swollen (enlarged) liver or abdomen, swollen feet and ankles and weight gain. The predisposing factors include high blood pressure, diabetes, sleep apnea, alcohol use and irregular heartbeats. Treatment includes surgery, vasodilator, beta blockers and diuretics.

Epiglottitis is a potentially life-threatening condition that occurs when the epiglottis — a small cartilage "lid" that covers your windpipe — swells, blocking the flow of air into your lungs.

A number of factors can cause the epiglottis to swell — burns from hot liquids, direct injury to your throat and various infections. The most common cause of epiglottitis in children in the past was infection with Haemophilus influenzae type b (Hib), the same bacterium that causes pneumonia, meningitis and infections in the bloodstream. Epiglottitis can occur at any age.

Routine Hib vaccination for infants has made epiglottitis rare, but epiglottitis remains a concern. If you suspect that you or someone in your family has epiglottitis, seek emergency help immediately. Prompt treatment can prevent life-threatening complications.

Esophageal cancer is cancer that occurs in the esophagus — a long, hollow tube that runs from your throat to your stomach. Your esophagus helps move the food you swallow from the back of your throat to your stomach to be digested.

Esophageal cancer usually begins in the cells that line the inside of the esophagus. Esophageal cancer can occur anywhere along the esophagus. More men than women get esophageal cancer.

Esophageal cancer is the sixth most common cause of cancer deaths worldwide. Incidence rates vary within different geographic locations. In some regions, higher rates of esophageal cancer cases may be attributed to tobacco and alcohol use or particular nutritional habits and obesity.

Normally, contractions of the esophagus camera.gif (the tube that connects the mouth and the stomach) move food from the mouth to the stomach with a regular, coordinated rhythm.

Esophageal spasm means that contractions of the esophagus are irregular, uncoordinated, and sometimes powerful. This condition may be called diffuse esophageal spasm, or DES. These spasms can prevent food from reaching the stomach. When this happens, the food gets stuck in the esophagus.

Sometimes the squeezing moves down the esophagus in a coordinated way, but it is very strong. This can be called nutcracker esophagus. These contractions move food through the esophagus but can cause severe pain.

Esophageal varices are abnormal, enlarged veins in the tube that connects the throat and stomach (esophagus). This condition occurs most often in people with serious liver diseases.

Esophageal varices develop when normal blood flow to the liver is blocked by a clot or scar tissue in the liver. To go around the blockages, blood flows into smaller blood vessels that aren't designed to carry large volumes of blood. The vessels can leak blood or even rupture, causing life-threatening bleeding.

A number of drugs and medical procedures can help prevent and stop bleeding from esophageal varices.

Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic shaking. It can affect almost any part of your body, but the trembling occurs most often in your hands — especially when you do simple tasks, such as drinking from a glass or tying shoelaces.

It's usually not a dangerous condition, but essential tremor typically worsens over time and can be severe in some people. Other conditions don't cause essential tremor, although it's sometimes confused with Parkinson's disease.

Esthesioneuroblastoma (es-THEE-zee-o-NOO-row-blas-TOE-muh) is a rare type of cancer that begins in the upper portion of the nasal cavity.

The area where esthesioneuroblastoma begins is separated from the brain by a bone that contains tiny holes that allow the nerves that control smell (olfactory nerves) to pass through. Esthesioneuroblastoma is also called olfactory neuroblastoma.

Esthesioneuroblastoma, which can occur at any age in adults, generally begins as a tumor in the nasal cavity and may grow or extend into the sinus, eyes and brain. People with esthesioneuroblastoma can lose their sense of smell, have frequent nosebleeds and experience difficulty breathing through their nostrils as the tumor grows.

Esthesioneuroblastoma can also spread to the lymph nodes in the neck and the parotid glands. In advanced cases, esthesioneuroblastoma can spread to other parts of the brain and other parts of the body, such as the lungs, liver and bones.

Esthesioneuroblastoma treatment usually includes surgery. Often, radiation and chemotherapy are recommended, as well.

Exercise headaches occur during or after sustained, strenuous exercise. Some activities associated with exercise headaches include running, rowing, tennis, swimming and weightlifting.

Doctors divide exercise headaches into two categories. Primary exercise headaches are usually harmless, aren't connected to any underlying problems and can often be prevented with medication.

Secondary exercise headaches are caused by an underlying, often serious problem within the brain — such as bleeding or a tumor — or outside the brain — such as coronary artery disease. Secondary exercise headaches may require emergency medical attention.

Eye floaters appear as small spots that drift through your field of vision. They may stand out when you look at something bright, like white paper or a blue sky. They might annoy you, but they shouldn’t interfere with your sight.

If you have a large floater, it can cast a slight shadow over your vision. But this tends to happen only in certain types of light.

You can learn to live with floaters and ignore them. You may notice them less as time passes. Only rarely do they get bad enough to require treatment.

The term eye strain is frequently used by people to describe a group of vague symptoms that are related to use of the eyes. Eye strain is a symptom, not an eye disease. Eye strain occurs when your eyes get tired from intense use, such as driving a car for extended periods, reading, or working at the computer. If you have any eye discomfort caused by looking at something for a long time, you can call it eye strain.

Although eye strain can be annoying, it usually is not serious and goes away once you rest your eyes. In some cases, signs and symptoms of eye strain are a sign of an underlying eye condition that needs treatment. Although you may not be able to change the nature of your job or all the factors that can cause eye strain, you can take steps to reduce eye strain.

Factitious disorder is a serious mental disorder in which someone deceives others by appearing sick, by purposely getting sick or by self-injury. Factitious disorder also can happen when family members or caregivers falsely present others, such as children, as being ill, injured or impaired.

Factitious disorder symptoms can range from mild (slight exaggeration of symptoms) to severe (previously called Munchausen syndrome). The person may make up symptoms or even tamper with medical tests to convince others that treatment, such as high-risk surgery, is needed.

Factitious disorder is not the same as inventing medical problems for practical benefit, such as getting out of work or winning a lawsuit. Although people with factitious disorder know they are causing their symptoms or illnesses, they may not understand the reasons for their behaviors or recognize themselves as having a problem.

Factitious disorder is challenging to identify and hard to treat. However, medical and psychiatric help are critical for preventing serious injury and even death caused by the self-harm typical of this disorder.

Farsightedness (hyperopia) is a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry.

The degree of your farsightedness influences your focusing ability. People with severe farsightedness may see clearly only objects a great distance away, while those with mild farsightedness may be able to clearly see objects that are closer.

Farsightedness usually is present at birth and tends to run in families. You can easily correct this condition with eyeglasses or contact lenses. Another treatment option is surgery.

A febrile seizure is a convulsion in a child that may be caused by a spike in body temperature, often from an infection. Your child's having a febrile seizure can be alarming, and the few minutes it lasts can seem like an eternity.

Febrile seizures represent a unique response of a child's brain to fever, usually the first day of a fever. Fortunately, they're usually harmless and typically don't indicate an ongoing problem. You can help by keeping your child safe during a febrile seizure and by comforting him or her afterward.

Fecal incontinence is the inability to control bowel movements, causing stool (feces) to leak unexpectedly from the rectum. Also called bowel incontinence, fecal incontinence ranges from an occasional leakage of stool while passing gas to a complete loss of bowel control.

Common causes of fecal incontinence include diarrhea, constipation, and muscle or nerve damage. The muscle or nerve damage may be associated with aging or with giving birth.

Whatever the cause, fecal incontinence can be embarrassing. But don't shy away from talking to your doctor. Treatments are available that can improve fecal incontinence and your quality of life.

Infertility is defined as trying to get pregnant (with frequent intercourse) for at least a year with no success. Female infertility, male infertility or a combination of the two affects millions of couples in the United States. An estimated 10 to 18 percent of couples have trouble getting pregnant or having a successful delivery.

Infertility results from female factors about one-third of the time and male factors about one-third of the time. The cause is either unknown or a combination of male and female factors in the remaining cases.

Female infertility causes can be difficult to diagnose. There are many available treatments, which will depend on the cause of infertility. Many infertile couples will go on to conceive a child without treatment. After trying to get pregnant for two years, about 95 percent of couples successfully conceive.

A sexual problem, or sexual dysfunction, refers to a problem during any phase of the sexual response cycle that prevents the individual or couple from experiencing satisfaction from the sexual activity. The sexual response cycle has four phases: excitement, plateau, orgasm, and resolution.

While research suggests that sexual dysfunction is common (43% of women and 31% of men report some degree of difficulty), it is a topic that many people are hesitant or embarrassed to discuss. Fortunately, most cases of sexual dysfunction are treatable, so it is important to share your concerns with your partner and doctor.

The term "fetal macrosomia" is used to describe a newborn who's significantly larger than average.

A baby diagnosed with fetal macrosomia has a birth weight of more than 8 pounds, 13 ounces (4,000 grams), regardless of his or her gestational age. About 9 percent of babies born worldwide weigh more than 8 pounds, 13 ounces.

However, the risks associated with fetal macrosomia increase greatly when birth weight is more than 9 pounds 15 ounces (4,500 grams).

Fetal macrosomia may complicate vaginal delivery and could put the baby at risk of injury during birth. Fetal macrosomia also puts the baby at increased risk of health problems after birth.

Fibroadenomas (fy-broe-ad-uh-NO-muhz) are solid, noncancerous breast lumps that occur most often in women between the ages of 15 and 35.

A fibroadenoma might feel firm, smooth, rubbery or hard and has a well-defined shape. Usually painless, it might feel like a marble in your breast, moving easily under your skin when examined. Fibroadenomas vary in size, and they can enlarge or shrink on their own.

Fibroadenomas are among the most common noncancerous (benign) breast lumps in young women. Treatment might include monitoring to detect changes in size or feel, a biopsy to evaluate the lump or surgery to remove it.

Fibrocystic breasts are composed of tissue that feels lumpy or rope-like in texture. Doctors call this nodular or glandular breast tissue.

It's not at all uncommon to have fibrocystic breasts. More than half of women experience fibrocystic breast changes at some point in their lives. In fact, medical professionals have stopped using the term "fibrocystic breast disease" and now simply refer to "fibrocystic breasts" or "fibrocystic breast changes" because having fibrocystic breasts isn't really a disease. Breast changes categorized as fibrocystic are considered normal.

Although many women with fibrocystic breasts don't have symptoms, some women experience breast pain, tenderness and lumpiness — especially in the upper, outer area of the breasts. Breast symptoms tend to be most bothersome just before menstruation. Simple self-care measures can usually relieve discomfort associated with fibrocystic breasts.

You have flatfeet when the arches on the inside of your feet are flattened, allowing the entire soles of your feet to touch the floor when you stand up.

A common and usually painless condition, flatfeet can occur when the arches don't develop during childhood. In other cases, flatfeet develop after an injury or from the simple wear-and-tear stresses of age.

Flatfeet can sometimes contribute to problems in your ankles and knees because the condition can alter the alignment of your legs. If you aren't having pain, no treatment is usually necessary for flatfeet.

Frostbite occurs when the skin is exposed to extreme or prolonged cold. The skin freezes, as do tissues beneath the surface of the skin. In extreme cases, muscle, nerves, and blood vessels may also freeze.

Skin may freeze within minutes when exposed to temperatures that fall below freezing. Even if temperatures are above freezing, the skin is likely to freeze if it’s wet or exposed to severe wind chills.

Frostbite also occurs when your skin directly contacts very cold surfaces. This type of exposure may immediately freeze the skin that touches the frozen surface.

Frozen shoulder is the common name for adhesive capsulitis, which is a shoulder condition that limits your range of motion. When the tissues in your shoulder joint become thicker and tighter, scar tissue develops over time. As a result, your shoulder joint doesn’t have enough space to rotate properly. Common symptoms include swelling, pain, and stiffness. You’re more likely to have the condition if you’re between the ages of 40 and 60.

Galactorrhea (guh-lack-toe-REE-uh) is a milky nipple discharge unrelated to the normal milk production of breast-feeding. Galactorrhea itself isn't a disease, but it could be a sign of an underlying problem. It usually occurs in women, even those who have never had children or after menopause. But galactorrhea can happen in men and even in infants.

Excessive breast stimulation, medication side effects or disorders of the pituitary gland all may contribute to galactorrhea. Often, galactorrhea results from increased levels of prolactin, the hormone that stimulates milk production.

Gallbladder cancer is cancer that begins in the gallbladder.

Your gallbladder is a small, pear-shaped organ on the right side of your abdomen, just beneath your liver. The gallbladder stores bile, a digestive fluid produced by your liver.

Gallbladder cancer is uncommon. When gallbladder cancer is discovered at its earliest stages, the chance for a cure is very good. But most gallbladder cancers are discovered at a late stage, when the prognosis is often very poor.

Gallbladder cancer is difficult to diagnose because it often causes no specific signs or symptoms. Also, the relatively hidden nature of the gallbladder makes it easier for gallbladder cancer to grow without being detected.

Gangrene is a condition that occurs when body tissue dies. It is caused by a loss of blood supply due to an underlying illness, injury, and/or infection. Fingers, toes, and limbs are most often affected, but gangrene can also occur inside the body, damaging organs and muscles. There are different types of gangrene and all require immediate medical attention.

Gastrointestinal (GI) bleeding is a symptom of a disorder in your digestive tract. The blood often appears in stool or vomit but isn't always visible, though it may cause the stool to look black or tarry. The level of bleeding can range from mild to severe and life-threatening.

Bleeding in the stomach or colon can usually be easily identified, but finding the cause of bleeding that occurs in the small intestine can be difficult. But sophisticated imaging technology can usually locate the problem, and minimally invasive procedures often can fix it.

Foot corns are hardened layers of skin that develop from your skin’s response to friction and pressure. You may have foot corns if you experience the following symptoms on the tips and the sides of your toes:

rough, tough, yellowing patch of lumpy or bumpy skin

skin that’s sensitive to touch

pain when wearing shoes

Foot corns can be safely treated, and you can even prevent future ones. Keep reading to learn tips on how you can manage existing corns and minimize your chances of developing new ones.

Gastroparesis means weakness of the muscles of the stomach. Gastroparesis results in poor grinding of food in the stomach into small particles and slow emptying of food from the stomach into the small intestine.

The stomach is a hollow organ composed primarily of muscle. Solid food that has been swallowed is stored in the stomach while it is ground into tiny pieces by the constant churning generated by rhythmic contractions of the stomach's muscles. Smaller particles are digested better in the small intestine than larger particles, and only food that has been ground into small particles is emptied from the stomach and well digested. Liquid food does not require grinding.

The ground solid and liquid food is emptied from the stomach into the small intestine slowly in a metered fashion. The metering process allows the emptied food to be well-mixed with the digestive juices of the small intestine, pancreas, and liver (bile) and to be absorbed well from the intestine. The metering process by which solid and liquid foods are emptied from the stomach is a result of a combination of relaxation of the muscle in parts of the stomach designed to accommodate (store) food, and the pressure generated by the muscle in other parts of the stomach that pushes the food into the small intestine. (Thus, the stomach can store and empty food at the same time.) The metering also is controlled by the opening and closing of the pylorus, the muscular opening of the stomach into the small intestine.

When the contractions of the stomach's muscles are weakened, food is not thoroughly ground and does not empty into the intestine normally. Since the muscular actions whereby solid food and liquid food are emptied from the stomach are slightly different, the emptying of solids and liquids follows different time courses, and there may be slow emptying of solid food (most common), solid and liquid food (less common), or liquid food alone (least common).

Gaucher (go-SHAY) disease is the result of a buildup of certain fatty substances in certain organs, particularly your spleen and liver. This causes these organs to enlarge and can affect their function.

The fatty substances also can build up in bone tissue, weakening the bone and increasing the risk of fractures. If the bone marrow is affected, it can interfere with your blood's ability to clot.

An enzyme that breaks down these fatty substances doesn't work properly in people with Gaucher disease. Treatment often includes enzyme replacement therapy.

An inherited disorder, Gaucher disease is most common in Jewish people of Eastern and Central European descent (Ashkenazi). Symptoms can appear at any age.

Genital herpes is a common sexually transmitted infection caused by the herpes simplex virus (HSV). Sexual contact is the primary way that the virus spreads. After the initial infection, the virus lies dormant in your body and can reactivate several times a year.

Genital herpes can cause pain, itching and sores in your genital area. But you may have no signs or symptoms of genital herpes. If infected, you can be contagious even if you have no visible sores.

There's no cure for genital herpes, but medications can ease symptoms and reduce the risk of infecting others. Condoms also can help prevent the spread of a genital herpes infection.

Geographic tongue is the name of a condition that gets its name from its map-like appearance on the upper surface and sides of the tongue. It may occur in other areas of your mouth, as well.

You'll be relieved to know that geographic tongue is a harmless, benign condition that isn't linked to any infection or cancer. Two other names for geographic tongue are benign migratory glossitis and erythema migrans.

Affecting about 1% to 3% of people, geographic tongue can show up at any age. However, it tends to affect middle-aged or older adults more often. It appears to be more common in women than in men.

Germ cell tumors are growths that form from reproductive cells. Tumors may be cancerous or noncancerous. Most germ cell tumors that are cancerous occur as cancer of the testicles (testicular cancer) or cancer of the ovaries (ovarian cancer).

Some germ cell tumors occur in other areas of the body, such as the abdomen, brain and chest, though it's not clear why. Germ cell tumors that occur in places other than the testicles and ovaries (extragonadal germ cell tumors) are very rare.

Germ cell tumors tend to respond to treatment and many can be cured, even when diagnosed at a late stage.

Glomerulonephritis (gloe-mer-u-low-nuh-FRY-tis) is inflammation of the tiny filters in your kidneys (glomeruli). Glomeruli remove excess fluid, electrolytes and waste from your bloodstream and pass them into your urine. Glomerulonephritis can come on suddenly (acute) or gradually (chronic).

Glomerulonephritis occurs on its own or as part of another disease, such as lupus or diabetes. Severe or prolonged inflammation associated with glomerulonephritis can damage your kidneys. Treatment depends on the type of glomerulonephritis you have.

Golfers elbow or medial epicondylitis is an overuse injury similar to tennis elbow (on the outside of the arm) but causing pain on the inside of the elbow instead. It is sometimes known as throwers elbow or little league elbow. We explain the symptoms, causes and treatment to return you back to full fitness in the shortest time.

Coronary artery disease (CAD), also known as ischemic heart disease (IHD),[13] is a group of diseases that includes: stable angina, unstable angina, myocardial infarction, and sudden cardiac death.[14] It is within the group of cardiovascular diseases of which it is the most common type

Signs and symptoms[edit]

Chest pain that occurs regularly with activity, after eating, or at other predictable times is termed stable angina and is associated with narrowings of the arteries of the heart.

Angina that changes in intensity, character or frequency is termed unstable. Unstable angina may precede myocardial infarction. In adults who go to the emergency department with an unclear cause of pain, about 30% have pain due to coronary artery disease

How Does Coronary Artery Disease Develop?

From a young age, plaque can start to go into your blood vessel walls. As you get older, the plaque builds up. 

A grand mal seizure causes a loss of consciousness and violent muscle contractions. It's the type of seizure most people picture when they think about seizures.

A grand mal seizure — also known as a generalized tonic-clonic seizure — is caused by abnormal electrical activity throughout the brain. Usually, a grand mal seizure is caused by epilepsy. But sometimes, this type of seizure can be triggered by other health problems, such as extremely low blood sugar, a high fever or a stroke.

Many people who have a grand mal seizure never have another one and don't need treatment. But someone who has recurrent seizures may need treatment with daily anti-seizure medications to control and prevent future grand mal seizures.

Granuloma annulare (gran-u-LOW-muh an-u-LAR-e) is a skin condition that most commonly consists of raised, reddish or skin-colored bumps (lesions) that form ring patterns — usually on your hands and feet.

No one knows exactly what causes granuloma annulare. But it may be triggered by minor skin injuries and certain medications. Some types of granuloma annulare affect adults, and others typically affect children.

In most cases, granuloma annulare isn't itchy or painful, so no treatment is necessary. The lesions usually disappear on their own within two years. If you're bothered by how your skin looks, your doctor can prescribe medications that will speed the disappearance of the lesions.

Greenstick fractures occur when the force applied to a bone results in bending of the bone such that the structural integrity of the convex surface is overcome. The fact that the integrity of the cortex has been overcome results in fracture of the convex surface. However, the bending force applied does not break the bone completely and the concave surface of the bent bone remains intact.

This can occur following an angulated longitudinal force applied down the bone (e.g. an indirect trauma following a fall on an outstretched arm), or after a force applied perpendicular to the bone (e.g. a direct blow).

This fracture is very different, and much less common, than the torus fracture that results in buckling of the cortex on the concave side of the bend and an intact concave surface.

Hangovers can occur at any time of day, but are usually more common in the morning directly after a night of heavy drinking.

As well as physical symptoms, the person may experience elevated levels of anxiety, regret, shame, embarrassment, and depression. The severity of a hangover is closely linked to how much alcohol was consumed, and whether the sufferer had enough sleep; the less sleep, the worse the hangover.

It is impossible really to say how much alcohol can be safely consumed to avoid a hangover - it depends on the individual and other factors, such as how tired they were before they began drinking, whether they were already dehydrated before the drinking began, whether they drank plenty of water during their drinking session, and how much sleep they got 

Heart rhythm problems (heart arrhythmias) occur when the electrical impulses that coordinate your heartbeats don't work properly, causing your heart to beat too fast, too slow or irregularly.

Heart arrhythmias (uh-RITH-me-uhs) may feel like a fluttering or racing heart and may be harmless. However, some heart arrhythmias may cause bothersome — sometimes even life-threatening — signs and symptoms.

Heart arrhythmia treatment can often control or eliminate fast, slow or irregular heartbeats. In addition, because troublesome heart arrhythmias are often made worse — or are even caused — by a weak or damaged heart, you may be able to reduce your arrhythmia risk by adopting a heart-healthy lifestyle.

Heat exhaustion is a condition whose symptoms may include heavy sweating and a rapid pulse, a result of your body overheating. It's one of three heat-related syndromes, with heat cramps being the mildest and heatstroke being the most severe.

Causes of heat exhaustion include exposure to high temperatures, particularly when combined with high humidity, and strenuous physical activity. Without prompt treatment, heat exhaustion can lead to heatstroke, a life-threatening condition. Fortunately, heat exhaustion is preventable.

Many different types of skin rashes exist. They can be concerning, uncomfortable, or downright painful. One of the most common types of rash is heat rash, or miliaria.

Heat rash is a skin condition that often affects children and adults in hot, humid weather conditions. You can develop heat rash when your pores become blocked and sweat can’t escape.

The cause of heat rash is often friction on the surface of the skin. Adults usually develop heat rash in the parts of their bodies that rub together, such as between the inner thighs or under the arms. Babies often develop heat rash on their necks, but it can also develop in skin folds such as the armpits, elbows, and thighs.

Hemangiomas, or infantile hemangiomas, are noncancerous growths of blood vessels. They’re the most common growths or tumors in children. They usually grow for a period of time and then subside without treatment.

They don’t cause problems in most infants. However, some hemangiomas may open and bleed or ulcerate. This may be painful. Depending on their size and location, they may be disfiguring. Additionally, they may occur with other abnormalities of the central nervous system or spine.

The growths may also occur with other internal hemangiomas. These affect internal organs such as the liver, other parts of the gastrointestinal system, the brain, or organs of the respiratory system. The hemangiomas that affect organs usually don’t cause problems.

Hemifacial spasms happen when the muscles on only one side of your face twitch without warning. These types of spasms are caused by damage or irritation to the facial nerve, which is also known as the seventh cranial nerve. Facial spasms occur when the muscles contract involuntarily because of this nerve irritation.

Hemifacial spasms are also known as tic convulsif. At first, they may appear only as small, barely noticeable tics around your eyelid, cheek, or mouth. Over time, the tics may expand to other parts of your face.

Hemifacial spasms can happen to men or women, but they’re most common in women over 40. They also tend to occur more often on the left side of your face. 

Hemifacial spasms aren’t dangerous on their own. But a constant twitch in your face can be frustrating or uncomfortable. In severe cases, these spasms can limit function due to involuntary eye closing or the impact they have on speaking.

In some cases, these spasms may indicate that you have an underlying condition or an abnormality in your facial structure. Either of these causes can compress or damage your nerves and make your face muscles twitch.

Hemophilia is not one disease but rather one of a group of inherited bleeding disorders that cause abnormal or exaggerated bleeding and poor blood clotting. The term is most commonly used to refer to two specific conditions known as hemophilia A and hemophilia B, which will be the main subjects of this article. Hemophilia A and B are distinguished by the specific gene that is mutated (altered to become defective) and codes for a defective clotting factor (protein) in each disease. Rarely, hemophilia C (a deficiency of Factor XI) is encountered, but its effect on clotting is far less pronounced than A or B.

Hemophilia A and B are inherited in an X-linked recessive genetic pattern and are therefore much more common in males. This pattern of inheritance means that a given gene on the X chromosome expresses itself only when there is no normal gene present. For example, a boy has only one X chromosome, so a boy with hemophilia has the defective gene on his sole X chromosome (and so is said to be hemizygous for hemophilia). Hemophilia is the most common X-linked genetic disease.

Although it is much rarer, a girl can have hemophilia, but she would have to have the defective gene on both of her X chromosomes or have one hemophilia gene plus a lost or defective copy of the second X chromosome that should be carrying the normal genes. If a girl has one copy of the defective gene on one of her X chromosomes and a normal second X chromosome, she does not have hemophilia but is said to be heterozygous for hemophilia (a carrier). Her male children have a 50% chance of inheriting the one mutated X gene and thus have a 50% chance of inheriting hemophilia from their carrier mother.

Hemophilia A occurs in about 1 out of every 5000 live male births. Hemophilia A and B occurs in all racial groups. Hemophilia A is about four times more common than B. B occurs in about 1 out of 20- 30,000 live male births.

Hemophilia has been called the Royal Disease because Queen Victoria, Queen of England from 1837 to 1901, was a carrier. Her daughters passed the mutated gene on to members of the royal families of Germany, Spain, and Russia. Alexandra, Queen Victoria's granddaughter, who became Tsarina of Russia in the early 20th century when she married Tsar Nicholas II, was a carrier. Their son, the Tsarevich Alexei, suffered from hemophilia.

Hepatitis A is a virus, or infection, that causes liver disease and inflammation of the liver. Viruses can cause sickness. For example, the flu is caused by a virus. People can pass viruses to each other.

Inflammation is swelling that occurs when tissues of the body become injured or infected. Inflammation can cause organs to not work properly.

A herniated disk refers to a problem with one of the rubbery cushions (disks) between the individual bones (vertebrae) that stack up to make your spine.

A spinal disk is a little like a jelly donut, with a softer center encased within a tougher exterior. Sometimes called a slipped disk or a ruptured disk, a herniated disk occurs when some of the softer "jelly" pushes out through a tear in the tougher exterior.

A herniated disk can irritate nearby nerves and result in pain, numbness or weakness in an arm or leg. On the other hand, many people experience no symptoms from a herniated disk. Most people who have a herniated disk don't need surgery to correct the problem.

Hidradenitis suppurativa (hi-drad-uh-NIE-tis sup-yoo-ruh-TIE-vuh) is rare, long-term skin condition that features small, painful lumps under the skin. They typically develop where the skin rubs together, such as the armpits, the groin, between the buttocks and under the breasts. The lumps may break open and smell or cause tunnels under the skin.

Hidradenitis suppurativa tends to start after puberty. It can persist for many years and worsen over time, with serious effects on your daily life and emotional well-being. Early diagnosis and treatment can help manage the symptoms, keep new lumps from forming and prevent complications, such as scar

A hip fracture is a serious injury, with complications that can be life-threatening. The risk of hip fracture rises with age.

Older people are at a higher risk of hip fracture because bones tend to weaken with age (osteoporosis). Multiple medications, poor vision and balance problems also make older people more likely to trip and fall — one of the most common causes of hip fracture.

A hip fracture almost always requires surgical repair or replacement, followed by months of physical therapy. Taking steps to maintain bone density and avoid falls can help prevent hip fracture.

Your hip is the joint where your thigh bone meets your pelvis. It is called a ball-and-socket joint, because the ball-like top of your thigh bone fits into a cup-like area within your pelvis, much like a baseball fits into a glove.

Normally, the ball glides smoothly within the socket, but a problem with the ball or socket rim can interfere with smooth motion. This problem can cause hip impingement or femoro acetabular impingement (FAI). It is believed to be a major cause of early osteoarthritis of the hip, particularly in those under age 40.

Your hip is the joint where your thigh bone meets your pelvis. It is called a ball-and-socket joint, because the ball-like top of your thigh bone fits into a cup-like area within your pelvis, much like a baseball fits into a glove.

Hip

Normally, the ball glides smoothly within the socket, but a problem with the ball or socket rim can interfere with smooth motion. This problem can cause hip impingement or femoro acetabular impingement (FAI). It is believed to be a major cause of early osteoarthritis of the hip, particularly in those under age 40.

Hives — also known as urticaria (ur-tih-KAR-e-uh) — is a skin reaction that causes itchy welts, which can range in size from small spots to large blotches several inches in diameter. Hives can be triggered by exposure to certain foods, medications or other substances.

Angioedema is a related type of swelling that affects deeper layers in your skin, often around your face and lips. In most cases, hives and angioedema are harmless and don't leave any lasting marks, even without treatment.

The most common treatment for hives and angioedema is antihistamine medication. Serious angioedema can be life-threatening if swelling causes your throat or tongue to block your airway.

Horner syndrome is a combination of signs and symptoms caused by the disruption of a nerve pathway from the brain to the face and eye on one side of the body.

Typically, Horner syndrome results in a decreased pupil size, a drooping eyelid and decreased sweating on the affected side of your face.

Horner syndrome is the result of another medical problem, such as a stroke, tumor or spinal cord injury. In some cases, no underlying cause can be found. There's no specific treatment for Horner syndrome, but treatment for the underlying cause may restore normal nerve function.

Horner syndrome is also known as Horner-Bernard syndrome or oculosympathetic palsy.

HPV infection commonly causes skin or mucous membrane growths (warts). Certain types of HPV infection cause cervical cancers. More than 100 varieties of human papillomavirus (HPV) exist.

Different types of HPV infection cause warts on different parts of your body. For example, some types of HPV infection cause plantar warts on the feet, while others cause warts that mostly appear on the face or neck.

Most HPV infections don't lead to cancer. But some types of genital HPV can cause cancer of the lower part of the uterus that connects to the vagina (cervix). Other types of cancers, including cancers of the anus, penis, vagina, vulva and back of the throat (oropharyngeal), have been linked to HPV infection.

Vaccines can help protect against the strains of genital HPV most likely to cause genital warts or cervical cancer.

Hunter syndrome is a very rare, inherited genetic disorder caused by a missing or malfunctioning enzyme. Because the body doesn't have enough of the enzyme to break down certain complex molecules, the molecules build up in harmful amounts.

In Hunter syndrome, the buildup of massive amounts of these harmful substances eventually causes permanent, progressive damage affecting appearance, mental development, organ function and physical abilities.

Hunter syndrome appears in children as young as 18 months. It mainly occurs in boys, although very rarely it has been observed in girls.

There's no cure for Hunter syndrome. Treatment of Hunter syndrome involves management of symptoms and complications.

Huntington's disease (HD) is a neurological condition. It is an inherited disease that happens due to faulty genes. Toxic proteins collect in the brain and cause damage, leading to neurological symptoms.

As parts of the brain deteriorate, this affects movement, behavior, and cognition. It becomes harder to walk, think, reason, swallow, and talk. Eventually, the person will need full-time care. The complications are usually fatal.

There is currently no cure, but treatment can help with symptoms.

A hydrocele is a sac filled with fluid that forms around a testicle. Hydroceles are most common in babies.

Nearly 10 percent of males are born with a hydrocele. However, they can affect males of any age.

Hydroceles generally don’t pose any threat to the testicles. They’re usually painless and disappear without treatment. However, if you have scrotal swelling, see your doctor to rule out other causes that are more harmful such as testicular cancer.

The term hydrocephalus is derived from the Greek words "hydro" meaning water and "cephalus" meaning head. As the name implies, it is a condition in which the primary characteristic is excessive accumulation of fluid in the brain. Although hydrocephalus was once known as "water on the brain," the "water" is actually cerebrospinal fluid (CSF)--a clear fluid that surrounds the brain and spinal cord. The excessive accumulation of CSF results in an abnormal widening of spaces in the brain called ventricles. This widening creates potentially harmful pressure on the tissues of the brain.

The ventricular system is made up of four ventricles connected by narrow passages.. Normally, CSF flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then reabsorbs into the bloodstream.

CSF has three important life-sustaining functions: 1) to keep the brain tissue buoyant, acting as a cushion or "shock absorber"; 2) to act as the vehicle for delivering nutrients to the brain and removing waste; and 3) to flow between the cranium and spine and compensate for changes in intracranial blood volume (the amount of blood within the brain).

The balance between production and absorption of CSF is critically important. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF. The resulting pressure of the fluid against brain tissue is what causes hydrocephalus.

One of the most common causes of high calcium levels (hypercalcemia), is an overproduction of parathyroid hormone, or hyperparathyroidism.

Hyperparathyroidism tends to be more common in women over 50.

It can be the result of all four parathyroid glands producing too much PTH (parathyroid hyperplasia), or one gland specifically producing an excessive amount of hormone (usually the result of a parathyroid adenoma, or benign tumor).

Hypercalcemia can occur due to other medical conditions. These conditions can vary in severity and chronicity, and may be life-threatening. Malignancy is a common cause of elevated blood calcium. Up to 20% of individuals with cancer will develop hypercalcemia at some point in their disease.

Think of your feet as your physical base; they're what keep you up and running. So if you're like most people, and don't think your feet need consistent care, think again. Cracked heels are one of the most common foot issues that can arise if you don't pay proper attention. But don't despair, baby soft foot skin is just one article away. Read on to learn more about how to get rid of annoying cracked skin around the heels.

Hypereosinophilic syndrome (HES) refers to a rare group of conditions that are associated with persistent eosinophilia with evidence of organ involvement. Signs and symptoms vary significantly based on which parts of the body are affected. Although any organ system can be involved in HES, the heart, central nervous system, skin, and respiratory tract are the most commonly affected. The condition was originally thought to be "idiopathic" or of unknown cause. However, recent advances in diagnostic testing have allowed a cause to be identified in approximately a quarter of cases. Management varies based on the severity of the condition and whether or not an underlying cause has been identified but generally includes imatinib or corticosteroids as an initial treatment.

High blood sugar (hyperglycemia) affects people who have diabetes. Several factors can contribute to hyperglycemia in people with diabetes, including food and physical activity choices, illness, nondiabetes medications, or skipping or not taking enough glucose-lowering medication.

It's important to treat hyperglycemia, because if left untreated, hyperglycemia can become severe and lead to serious complications requiring emergency care, such as a diabetic coma. In the long term, persistent hyperglycemia, even if not severe, can lead to complications affecting your eyes, kidneys, nerves and heart.

Hyperhidrosis, or excessive sweating, is a common disorder which produces a lot of unhappiness. An estimated 2%-3% of Americans suffer from excessive sweating of the underarms (axillary hyperhidrosis) or of the palms and soles of the feet (palmoplantar hyperhidrosis). Underarm problems tend to start in late adolescence, while palm and sole sweating often begins earlier, around age 13 (on the average). Untreated, these problems may continue throughout life.

Sweating is embarrassing, it stains clothes, ruins romance, and complicates business and social interactions. Severe cases can have serious practical consequences as well, making it hard for people who suffer from it to hold a pen, grip a car steering wheel, or shake hands.

Hyperparathyroidism is an excess of parathyroid hormone in the bloodstream due to overactivity of one or more of the body's four parathyroid glands. These glands are about the size of a grain of rice and are located in your neck.

The parathyroid glands produce parathyroid hormone, which helps maintain an appropriate balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning.

Two types of hyperparathyroidism exist. In primary hyperparathyroidism, an enlargement of one or more of the parathyroid glands causes overproduction of the hormone, resulting in high levels of calcium in the blood (hypercalcemia), which can cause a variety of health problems. Surgery is the most common treatment for primary hyperparathyroidism.

Secondary hyperparathyroidism occurs as a result of another disease that initially causes low levels of calcium in the body and over time, increased parathyroid hormone levels occur.

Hyponatremia is a condition that occurs when the level of sodium in your blood is abnormally low. Sodium is an electrolyte, and it helps regulate the amount of water that's in and around your cells.

In hyponatremia, one or more factors — ranging from an underlying medical condition to drinking too much water during endurance sports — causes the sodium in your body to become diluted. When this happens, your body's water levels rise, and your cells begin to swell. This swelling can cause many health problems, from mild to life-threatening.

Hyponatremia treatment is aimed at resolving the underlying condition. Depending on the cause of hyponatremia, you may simply need to cut back on how much you drink. In other cases of hyponatremia, you may need intravenous fluids and medications.

Hypothermia is defined as a body temperature (core, or internal body temperature) of less than about 95 F (35 C). Usually, hypothermia occurs when the body's temperature regulation is overwhelmed by a cold environment. However, in the medical and lay literature there are essentially two major classifications, accidental hypothermia and intentional hypothermia.

Accidental hypothermia usually occurs from an exposure to cold that results in lowering the body temperature.

Intentional hypothermia is body temperature lowering induced usually for a medical procedure.

This article will focus on accidental hypothermia. Hypothermia is a medical emergency that, when quickly and appropriately treated, people can recover with little or no consequences.

Body temperature, when discussing hypothermia, is usually termed "core" temperature. This temperature is the temperature measured inside the body. It's a measurement that is most accurately done by a rectal thermometer, a rectal probe thermometer that has a constant temperature readout or by a bladder or esophageal temperature device. Temperatures taken by other methods may not adequately measure core temperature.

Cradle cap causes crusty or oily scaly patches on a baby's scalp. The condition isn't painful or itchy. But it can cause thick white or yellow scales that aren't easy to remove.

Cradle cap usually clears up on its own in a few months. Home-care measures include washing your baby's scalp daily with a mild shampoo. This can help loosen and remove the scales. Don't scratch cradle cap.

If cradle cap persists or seems severe, your doctor may suggest a medicated shampoo, lotion or other 

Impetigo (im-puh-TIE-go) is a common and highly contagious skin infection that mainly affects infants and children. Impetigo usually appears as red sores on the face, especially around a child's nose and mouth, and on hands and feet. The sores burst and develop honey-colored crusts.

Treatment with antibiotics is generally recommended to help prevent the spread of impetigo to others. It's important to keep your child home from school or day care until he or she is no longer contagious — usually 24 hours after you begin antibiotic treatment.

An incompetent cervix, also called a cervical insufficiency, is a condition that occurs when weak cervical tissue causes or contributes to premature birth or the loss of an otherwise healthy pregnancy.

Before pregnancy, your cervix — the lower part of the uterus that connects to the vagina — is normally closed and rigid. As pregnancy progresses and you prepare to give birth, the cervix gradually softens, decreases in length (effaces) and opens (dilates). If you have an incompetent cervix, your cervix might begin to open too soon — causing you to give birth too early.

An incompetent cervix can be difficult to diagnose and, as a result, treat. If your cervix begins to open early, your health care provider might recommend preventive medication during pregnancy, frequent ultrasounds or a procedure that closes the cervix with strong sutures (cervical cerclage).

Jaundice is particularly common in premature babies - boys more often than girls. It usually appears within the baby's first week of life.

In an otherwise healthy baby born at full term, infant jaundice is rarely a cause for alarm; it tends to go away on its own. However, if treatment is necessary, infants tend to respond to non-invasive therapy.

In rare cases, untreated infant jaundice may lead to brain damage and even death.

Infant reflux occurs when food backs up (refluxes) from a baby's stomach, causing the baby to spit up. Sometimes called gastroesophageal reflux (GER), the condition is rarely serious and becomes less common as a baby gets older. It's unusual for infant reflux to continue after age 18 months.

Reflux occurs in healthy infants multiple times a day. As long as your baby is healthy, content and growing well, the reflux is not a cause for concern.

Rarely, infant reflux can be a sign of a medical problem, such as an allergy, a blockage in the digestive system or gastroesophageal reflux disease (GERD).

Infectious diseases kill more people worldwide than any other single cause. Infectious diseases are caused by germs. Germs are tiny living things that are found everywhere - in air, soil and water. You can get infected by touching, eating, drinking or breathing something that contains a germ. Germs can also spread through animal and insect bites, kissing and sexual contact. Vaccines, proper hand washing and medicines can help prevent infections.

You can also catch flu by touching an infected person, for instance, shaking hands. Adults are contagious 1-2 days before getting symptoms and up to 7 days after becoming ill. This means that you can spread the influenza virus before you even know you are infected.

In this article, we explain the symptoms of flu, how it is treated, how it differs from a cold, and the best ways to prevent flu occurring.

Ingrown toenails occur when the edges or corners of your nails grow into the skin next to the nail. Your big toe is most likely to get an ingrown toenail.

You can treat ingrown toenails at home. However, they can cause complications that might require medical treatment. Your risk of complications is higher if you have diabetes or other conditions that cause poo

An inguinal hernia occurs in the abdomen near the groin area. They develop when fatty or intestinal tissues push through a weakness in the abdominal wall near the right or left inguinal canal. Each inguinal canal resides at the base of the abdomen.

Both men and woman have inguinal canals. In men, the testes usually descend through their canal by around a few weeks before birth. In women, each canal is the location of passage for the round ligament of the uterus. If you have a hernia in or near this passageway, it results in a protruding bulge. It may be painful during movement.

Many people don’t seek treatment for this type of hernia because it may be small or not cause any symptoms. Prompt medical treatment can help prevent further protrusion and discomfort.

Interstitial (in-tur-STISH-ul) lung disease describes a large group of disorders, most of which cause progressive scarring of lung tissue. The scarring associated with interstitial lung disease eventually affects your ability to breathe and get enough oxygen into your bloodstream.

Interstitial lung disease can be caused by long-term exposure to hazardous materials, such as asbestos. Some types of autoimmune diseases, such as rheumatoid arthritis, also can cause interstitial lung disease. In some cases, however, the causes remain unknown.

Once lung scarring occurs, it's generally irreversible. Medications may slow the damage of interstitial lung disease, but many people never regain full use of their lungs. Lung transplant is an option for some people who have interstitial lung disease.

Intestinal ischemia (is-KEE-me-uh) describes a variety of conditions that occur when blood flow to your intestines decreases due to a blockage, usually in an artery. Intestinal ischemia can affect your small intestine, your large intestine (colon) or both.

Intestinal ischemia is a serious condition that can cause pain and make it difficult for your intestines to work. In severe cases, loss of blood flow to the intestines can damage intestinal tissue and lead to death.

Treatments are available for intestinal ischemia. To improve the chances of recovery, it's crucial to recognize the early symptoms and get medical help right away.

Creatinine is a chemical waste molecule that is generated from muscle metabolism.

Creatinine is produced from creatine, a molecule of major importance for energy production in muscles.

Approximately 2% of the body's creatine is converted to creatinine every day.

Creatinine is transported through the bloodstream to the kidneys. The kidneys filter out most of the creatinine and dispose of it in the urine.

Because the muscle mass in the body is relatively constant from day to day, the creatinine production normally remains essentially unchanged on a daily basis.

Digested food particles must travel through 25 feet or more of intestines as part of normal digestion. These digested wastes are constantly in motion. However, intestinal obstruction can put a stop to this. An intestinal obstruction occurs when your small or large intestine is blocked. The blockage can be partial or total, and it prevents passage of fluids and digested food.

If intestinal obstruction happens, food, fluids, gastric acids, and gas build up behind the site of the blockage. If enough pressure builds up, your intestine can rupture, leaking harmful intestinal contents and bacteria into your abdominal cavity. This is a life-threatening complication.

There are many potential causes of intestinal obstruction. Often, this condition can’t be prevented. Early diagnosis and treatment are crucial. An untreated intestinal obstruction can be fatal.

An intracranial hematoma is a collection of blood within the skull, most commonly caused by rupture of a blood vessel within the brain or from trauma such as a car accident or fall. The blood collection can be within the brain tissue or underneath the skull, pressing on the brain.

Although some head injuries — such as one that causes only a brief lapse of consciousness (concussion) — can be minor, an intracranial hematoma is potentially life-threatening. It usually requires immediate treatment, often surgery to remove the blood.

Intussusception (in-tuh-suh-SEP-shun) is the most common abdominal emergency affecting children under 2 years old. It happens when one portion of the bowel slides into the next, much like the pieces of a telescope.

When this "telescoping" happens, the flow of fluids and food through the bowel can become blocked, the intestine can swell and bleed, and the blood supply to the affected part of the intestine can get cut off. Eventually, this can cause part of the bowel to die.

Intussusception happens in 1 to 4 out of every 1,000 infants and is most common in babies 5 to 9 months old, though older children also can have it. Boys get intussusception more often than girls.

Invasive lobular carcinoma is a type of breast cancer that begins in the milk-producing glands (lobules) of the breast.

Invasive cancer means the cancer cells have broken out of the lobule where they began and have the potential to spread to the lymph nodes and other areas of the body.

Invasive lobular carcinoma makes up a small portion of all breast cancers. The most common type of breast cancer begins in the breast ducts (invasive ductal carcinoma).

Invasive lobular carcinoma typically doesn't form a lump, which is common in breast cancer. Instead, there is a change in the breast that feels like a thickening or fullness in one part of the breast and is different from the surrounding breast tissue.

Ischemic colitis occurs when blood flow to part of the large intestine (colon) is reduced, usually due to narrowed or blocked blood vessels (arteries). The diminished blood flow doesn't provide enough oxygen for the cells in your digestive system.

Ischemic colitis can cause pain and may damage your colon. Any part of the colon can be affected, but ischemic colitis usually causes pain on the left side of the belly area (abdomen).

The condition can be misdiagnosed because it can easily be confused with other digestive problems. Ischemic colitis may heal on its own. But you may need medication to treat ischemic colitis or prevent infection, or you may need surgery if your colon has been damaged.

Islet cell cancer is a term used to describe a group of cancers that can occur in the hormone-producing cells of the pancreas. Islet cell cancers, also known as pancreatic neuroendocrine tumors, are very rare.

Islet cells are small hormone-producing cells normally found in your pancreas. Islet cell cancer arises from these cells. Some islet cell cancer cells continue to secrete hormones, creating too much of the given hormone in your body. Examples of these types of islet cell cancers include gastrinoma and glucagonoma.

Jellyfish are a common sea creature found in every ocean. There are many species of jellyfish, all of them with tentacles. Some carry poisonous venom in their tentacles as a method of self-defense against predators. It’s this venom that makes a jellyfish sting so painful.

Most types of jellyfish stings will cause some discomfort, but some can be life-threatening. According to the National Science Foundation, over 500,000 people are stung by jellyfish every year in North America’s Chesapeake Bay alone.

Juvenile-onset fibromyalgia (JFM) is a poorly understood chronic pain condition most commonly affecting adolescent girls. The condition is characterized by widespread musculoskeletal pain and other associated symptoms, including fatigue, nonrestorative sleep, headaches, irritable bowel symptoms, dysautonomia and mood disorders such as anxiety and/or depression. In the past few years, there has been a greater focus on understanding JFM in adolescents. Research studies have provided insight into the clinical characteristics of this condition and its effect on both short-term and long-term psychosocial and physical functioning. The importance of early and effective intervention is being recognized, as research has shown that symptoms of JFM tend to persist and do not resolve over time as was previously believed. Efforts to improve treatments for JFM are underway, and new evidence strongly points to the potential benefits of cognitive–behavioural therapy on improving mood and daily functioning. Research into pharmacotherapy and other nonpharmacological options is in progress. Advancements in the understanding of adult fibromyalgia have paved the way for future studies on diagnosis, assessment and management of JFM. This Review focuses on our current knowledge of the condition, provides an update of the latest research advances, and highlights areas for further study.

Kawasaki disease is a rare childhood illness that affects the blood vessels. The symptoms can be severe for several days and can look scary to parents. But then most children return to normal activities.

Kawasaki disease can harm the coronary arteries, which carry blood to the heart muscle. Most children who are treated recover from the disease without long-term problems. Your doctor will watch your child for heart problems for a few weeks to a few months after treatment.

The disease is most common in children ages 1 to 2 years and is less common in children older than age 8. It does not spread from child to child (is not contagious).

Crohn's disease (sometimes called Crohn disease) is a chronic inflammatory disease of the intestines. It primarily causes ulcerations (breaks in the lining) of the small and large intestines, but can affect the digestive system anywhere from the mouth to the anus. It is named after the physician who described the disease in 1932. It also is called granulomatous enteritis or colitis, regional enteritis, ileitis, or terminal ileitis.

Crohn's disease is related closely to another chronic inflammatory condition that involves only the colon called ulcerative colitis. Together, Crohn's disease and ulcerative colitis are frequently referred to as inflammatory bowel disease (IBD). Ulcerative colitis and Crohn's disease have no medical cure. Once the diseases begin, they tend to fluctuate between periods of inactivity (remission) and activity (relapse).

 Men and women are affected equally by inflammatory bowel disease. Americans of Jewish European descent are more likely to develop IBD than the general population. IBD has historically been considered predominately disease of Caucasians, but there has been an increase in reported cases in African Americans suffering from IBD. The prevalence appears to be lower among Hispanic and Asian populations. IBD most commonly begins during adolescence and early adulthood (usually between the ages of 15 and 35). There is a small second peak of newly-diagnosed cases after age 50. The number of new cases (incidence) and number of cases (prevalence) of Crohn's disease in the United States are rising, although the reason for this is not completely understood.

Crohn's disease (sometimes called Crohn disease) is a chronic inflammatory disease of the intestines. It primarily causes ulcerations (breaks in the lining) of the small and large intestines, but can affect the digestive system anywhere from the mouth to the anus. It is named after the physician who described the disease in 1932. It also is called granulomatous enteritis or colitis, regional enteritis, ileitis, or terminal ileitis.

Crohn's disease is related closely to another chronic inflammatory condition that involves only the colon called ulcerative colitis. Together, Crohn's disease and ulcerative colitis are frequently referred to as inflammatory bowel disease (IBD). Ulcerative colitis and Crohn's disease have no medical cure. Once the diseases begin, they tend to fluctuate between periods of inactivity (remission) and activity (relapse).

 Men and women are affected equally by inflammatory bowel disease. Americans of Jewish European descent are more likely to develop IBD than the general population. IBD has historically been considered predominately disease of Caucasians, but there has been an increase in reported cases in African Americans suffering from IBD. The prevalence appears to be lower among Hispanic and Asian populations. IBD most commonly begins during adolescence and early adulthood (usually between the ages of 15 and 35). There is a small second peak of newly-diagnosed cases after age 50. The number of new cases (incidence) and number of cases (prevalence) of Crohn's disease in the United States are rising, although the reason for this is not completely understood.

Keratitis is the medical term for inflammation of the cornea. The cornea is the dome-shaped window in the front of the eye. When looking at a person's eye, one can see the iris and pupil through the normally clear cornea. The cornea bends light rays as a result of its curved shape and accounts for approximately two-thirds of the eye's total optical power, with the lens of the eye contributing the remaining one-third. Only the very thin tear film lies between the front of the cornea and our environment.

The cornea is about 0.5 millimeter thick. The back of the cornea is bathed in the aqueous fluid that fills the anterior chamber of the eye. The cornea has a diameter of about 13 millimeters (½ inch) and, together with the sclera (the white part of the eye) forms the entire outer coat of the eye.

We see through the cornea, which is the clear outer lens or "windshield" of the eye. Normally, the cornea has a dome shape, like a ball. Sometimes, however, the structure of the cornea is just not strong enough to hold this round shape and the cornea bulges outward like a cone. This condition is called keratoconus.

Kidney cancer -- also called renal cancer -- is a disease in which kidney cells become malignant (cancerous) and grow out of control, forming a tumor. Almost all kidney cancers first appear in the lining of tiny tubes (tubules) in the kidney. This type of kidney cancer is called renal cell carcinoma. The good news is that most of kidney cancers are found before they spread (metastasize) to distant organs. And cancers caught early are easier to treat successfully. However, these tumors can grow to be quite large before they are detected.

The kidneys are two bean-shaped organs, each about the size of a fist. They lie in your lower abdomen on each side of your spine. Their main job is to clean your blood, removing waste products and making urine.

A simple kidney cyst is a round pouch of smooth, thin-walled tissue or a closed pocket that is usually filled with fluid. One or more may form within the kidneys. Simple cysts are the most common type of kidney cyst. They are not the same thing as polycystic kidney disease, which is a progressive disease that can lead to kidney failure. Simple kidney cysts most often do not cause harm.

Kleptomania (klep-toe-MAY-nee-uh) is the recurrent inability to resist urges to steal items that you generally don't really need and that usually have little value. Kleptomania is a rare but serious mental health disorder that can cause much emotional pain to you and your loved ones if not treated.

Kleptomania is a type of impulse control disorder — a disorder that's characterized by problems with emotional or behavioral self-control. If you have an impulse control disorder, you have difficulty resisting the temptation or drive to perform an act that's excessive or harmful to you or someone else.

Many people with kleptomania live lives of secret shame because they're afraid to seek mental health treatment. Although there's no cure for kleptomania, treatment with medication or talk therapy (psychotherapy) may help to end the cycle of compulsive stealing.

A bursa is a closed, fluid-filled sac that functions as a gliding surface to reduce friction between tissues of the body. Bursae is plural for bursa. The major bursae are located adjacent to the tendons near the large joints, such as the shoulders, elbows, hips, and knees. When a bursa becomes inflamed, the condition is known as bursitis. Most commonly, bursitis is caused by local soft-tissue trauma or strain injury, and there is no infection (aseptic bursitis). On rare occasions, particularly when the immune system is suppressed, the bursa can become infected with bacteria. This condition is called septic bursitis.

Krabbe disease, also known as globoid cell leukodystrophy or galactosylceramide lipidosis, is an autosomal-recessive sphingolipidosis caused by deficient activity of the lysosomal hydrolase galactosylceramide beta-galactosidase (GALC). GALC degrades galactosylceramide, a major component of myelin, and other terminal beta-galactose–containing sphingolipids, including psychosine (galactosylsphingosine). Increased psychosine levels are believed to lead to widespread destruction of oligodendroglia in the CNS and to subsequent demyelination. [1, 2, 3]

Krabbe originally described a condition with infantile onset that was characterized by spasticity and a rapidly progressive neurologic degeneration leading to death. Since the original description, numerous cases have been documented that show a wide distribution in age of onset.

Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses or contact lenses and is not due to any eye disease. The brain, for some reason, does not fully acknowledge the images seen by the amblyopic eye. This almost always affects only one eye but may manifest with reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.

Lead poisoning occurs when lead builds up in the body, often over months or years. Even small amounts of lead can cause serious health problems. Children younger than 6 years are especially vulnerable to lead poisoning, which can severely affect mental and physical development. At very high levels, lead poisoning can be fatal.

Lead-based paint and lead-contaminated dust in older buildings are the most common sources of lead poisoning in children. Other sources include contaminated air, water and soil. Adults who work with batteries, do home renovations or work in auto repair shops also might be exposed to lead.

There is treatment for lead poisoning, but taking some simple precautions can help protect you and your family from lead exposure before harm is done.

Oh, what a beautiful smile you have there. Every time you smile, your eyes light up. Ah, those crinkles at the corners of the eyes make you look prettier still.

Crow’s feet may or may not look charming, but if I’m guessing right, you would still want to iron them out. Want to know the best treatment for crows feet? Worry not! Have a look at these remedies I’ve gathered, and you can have your wish come true in no time.

Leiomyosarcoma (LMS) is a type of soft tissue sarcoma. Soft tissue sarcomas can develop in muscle, fat, blood vessels, or any of the other tissues that support, surround and protect the organs of the body.

Leiomyosarcoma is one of the more common types of soft tissue sarcoma to develop in adults. We don’t yet know the exact cause.

Leiomyosarcomas are usually treated at a specialist hospital. The usual treatment for a leiomyosarcoma is surgery to remove the tumour. You may have radiotherapy after surgery, to reduce the chance of the cancer coming back. Chemotherapy is also sometimes used for a leiomyosarcomas that has come back, or that has spread.

You may be asked to take part in clinical trial looking at new ways of treating leiomyosarcomas. Your doctor or specialist nurse can talk to you about this.

After treatment, you will have regular check-ups. If you have any problems or notice any new symptoms between these check-ups, it’s important to let your doctor know as soon as possible

Lewy body dementia (LBD) is a progressive brain disorder in which Lewy bodies (abnormal deposits of a protein called alpha-synuclein) build up in areas of the brain that regulate behavior, cognition, and movement.

A complex disease, LBD can present with a range of symptoms including problems with thinking, memory, moving, sleep and/or changes in behavior, to name a few of the physical, cognitive, and behavioral symptoms.

LBD also affects autonomic body functions, such as blood pressure control, temperature regulation, and bladder and bowel function. Progressively debilitating, LBD can also cause people to experience visual hallucinations or act out their dreams.

Lichen nitidus is an unusual/ rare non-infectious skin condition most commonly seen in children. It occurs in the form of hundreds and hundreds of tiny grids of bumps over the skin. They are often found in tight groups that appear like a big patch.

The arms and the folds of the skin are most commonly affected, but they can occur anywhere in the body. In fairer skinned people, these bumps are slightly reddish in color, whereas in darker skinned people, the bumps may vary between lighter or darker in color than the normal skin.

Lichen sclerosus (LIE-kun skluh-ROW-sus) is an uncommon condition that creates patchy, white skin that's thinner than normal. Lichen sclerosus can affect skin anywhere on your body. But it most often involves skin of the vulva, foreskin of the penis or skin around the anus.

Anyone can get lichen sclerosus but postmenopausal women have a high risk.

Sometimes lichen sclerosus improves on its own, and you won't need any treatment. If you do need treatment, your doctor can suggest options to return a more normal appearance to your skin and decrease the tendency for scarring.

Limited scleroderma, also known as CREST syndrome, is one subtype of scleroderma — a condition whose name means "hardened skin."

The skin changes associated with limited scleroderma typically occur only in the lower arms and legs, below the elbows and knees, and sometimes affect the face and neck. Limited scleroderma can also affect your digestive tract, heart, lungs or kidneys.

The problems caused by limited scleroderma may be minor. Sometimes, however, the disease affects the lungs or heart, with potentially serious results. Limited scleroderma has no known cure. Treatments focus on managing symptoms, preventing serious complications and improving quality of life.

Lip cancers are abnormal cells that grow out of control and form lesions or tumors on the lips. They are the most common type of oral cancers. These cancers develop in thin, flat cells — called squamous cells — that line the lips, mouth, tongue, cheeks, sinuses, throat, and hard and soft palates.

Lip cancer and other kinds of oral cancers are types of head and neck cancers.

Certain lifestyle choices, such as smoking, drinking, sun exposure, and tanning, increase your risk of developing lip cancer. Dentists are typically the first to notice signs of lip cancers, often during a routine dental exam.

Lip cancers are highly curable when diagnosed early.

Listeriosis is an infection caused by a gram stain-positive motile bacterium named Listeria monocytogenes. The foodborne illness produces fever, muscle aches, and, in many people, diarrhea. Severe infections can cause headaches, meningitis, convulsions, and death. Most healthy people exposed to the bacteria have minor or no symptoms, but a few people, especially the elderly, pregnant females and their fetus, newborns, and anyone with a compromised immune system are especially susceptible to these organisms. Listeria bacteria are widespread throughout the world and are often associated with farm animals that may show no signs of infection. Research shows that many animals are uninfected carriers, and they suggest that some humans carry these organisms as part of their bowel flora. Except for pregnant women and their fetus or newborn, there is no direct transfer of Listeria from human to human.

The organisms (Listeria monocytogenes) that cause listeriosis have probably been infecting humans for centuries. Listeria was first isolated from an infected WWI soldier in 1918 and had many different names until 1940, when the genus and species names were firmly established. However, the bacteria were first recognized as a food-borne (food poisoning) pathogen in 1979. The bacteria can penetrate human cells and can multiply inside them. People with altered or impaired immune systems have cells that are less able to control the spread of these organisms into the blood or into other cells. In 2010, a known species, Listeria ivanovii, thought only to infect cattle, was found to infect humans so there are two Listeria species that can infect humans.

Outbreaks of listeriosis can occur with some frequency. For example, in 2017, soft raw milk cheese was a source of an outbreak (Vulto Creamery). In this outbreak, eight people were infected and two died. Other recalls of products in 2017 include 3 tons of cheese for possible Listeria contamination (La Nica Products INC.), macadamia nuts (Simple Truth brand), Ava's Organic Cashews, and Queso Fresco cheese, for the same problem.

A liver hemangioma is a tangled network of blood vessels in or on the surface of the liver. This tumor is noncancerous and usually doesn’t cause symptoms. In fact, most people don’t even know they have a liver hemangioma. It’s usually only discovered during a test or procedure for an unrelated condition. Even when they’re diagnosed, most liver hemangiomas don’t require treatment.

A liver hemangioma is noncancerous and doesn’t increase your risk of developing cancer. The tumor is usually small, measuring less than 4 centimeters in diameter. In some cases, however, it can grow much larger. A larger tumor is more likely to cause symptoms, such as abdominal pain and nausea. Pregnant women and women using estrogen replacement therapy have a higher risk of developing a large hemangioma. This is because estrogen may contribute to the growth of liver hemangiomas.

Most people only have one liver hemangioma. However, it’s possible for several hemangiomas to form on the liver at once.

A liver hemangioma typically doesn’t cause complications in adults, but it can be more dangerous when it develops in infants. In babies, the growth is called infantile hemangioendothelioma. It’s usually diagnosed before the baby is 6 months old. This is a rare condition in infants. Although the tumor isn’t cancerous, it has been linked to higher rates of heart failure.

Long QT syndrome (LQTS) is a heart rhythm condition that can potentially cause fast, chaotic heartbeats. These rapid heartbeats might trigger a sudden fainting spell or seizure. In some cases, the heart can beat erratically for so long that it causes sudden death.

You can have a genetic mutation that puts you at risk of being born with congenital long QT syndrome. In addition, certain medications, imbalances of the body's salts and minerals (electrolyte abnormalities), and medical conditions might cause acquired long QT syndrome.

Long QT syndrome is treatable. You might need to take medications to prevent an erratic heart rhythm. In some cases, treatment for long QT syndrome involves surgery or an implantable device.

You'll also need to avoid certain medications that could trigger your long QT syndrome. After treatment, you likely can live and thrive, even with this condition. You may be able to continue being active in recreational — and even competitive — sports.

Answer: Low sperm count implies that the fluids (semen) you ejaculate in the course of an orgasm consist of lesser sperm when compared with normal.

A low sperm count can be referred to as oligospermia. A total lack of sperm is known as Azoospermia. Your own sperm count is regarded as less than normal when you have less than fifteen million sperm per millilitre of semen.

Having a low sperm count reduces the chances that one of your own sperm will certainly fertilize the partner’s egg, leading to pregnancy. Nevertheless, numerous males that have a low sperm count will still be in a position to father a baby.

Lupus nephritis is inflammation of the kidney that is caused by systemic lupus erythematous (SLE). Also called lupus, SLE is an autoimmune disease. With lupus, the body's immune system targets its own body tissues. Lupus nephritis happens when lupus involves the kidneys.

Up to 60% of lupus patients will develop lupus nephritis. When the kidneys are inflamed, they can't function normally and can leak protein. If not controlled, lupus nephritis can lead to kidney failure.

The lymphatic system is a network of specialized vessels (lymph vessels) throughout the body whose purpose is to collect excess lymph fluid with proteins, lipids, and waste products from the tissues. This fluid is then carried to the lymph nodes, which filter waste products and contain infection-fighting cells called lymphocytes. The excess fluid in the lymph vessels is eventually returned to the bloodstream. When the lymph vessels are blocked or unable to carry lymph fluid away from the tissues, localized swelling (lymphedema) is the result.

Lynch syndrome, often called hereditary nonpolyposis colorectal cancer (HNPCC), is an inherited disorder that increases the risk of many types of cancer, particularly cancers of the colon (large intestine) and rectum, which are collectively referred to as colorectal cancer. People with Lynch syndrome also have an increased risk of cancers of the stomach, small intestine, liver, gallbladder ducts, upper urinary tract, brain, and skin. Additionally, women with this disorder have a high risk of cancer of the ovaries and lining of the uterus (the endometrium). People with Lynch syndrome may occasionally have noncancerous (benign) growths (polyps) in the colon, called colon polyps. In individuals with this disorder, colon polyps occur earlier but not in greater numbers than they do in the general population.

Male breast cancer is a rare cancer that forms in the breast tissue of men. Though breast cancer is most commonly thought of as a woman's disease, male breast cancer does occur.Male breast cancer is most common in older men, though it can occur at any age.Men diagnosed with male breast cancerat an early stage have a good chance for a cure. Still, many men delay seeing their doctors if they notice one of the usual signs or symptoms, such as a breast lump. For this reason, many male breast cancers are diagnosed when the disease is more advanced.

Male hypogonadism is a condition in which the body doesn't produce enough testosterone — the hormone that plays a key role in masculine growth and development during puberty — or has an impaired ability to produce sperm orboth.You may be born with male hypogonadism, or it can develop later in life, often from injury or infection. The effects — and what you can do about them — depend on the cause and at what point in your life male hypogonadism occurs. Some types of male hypogonadism can be treated with testosterone replacement therapy.

Malignant hyperthermia is a condition that triggers a severe reaction to certain drugs used as part of anesthesia for surgery. Without prompt treatment, the disease can be fatal.The genes that cause malignant hyperthermia are inherited. In most cases, no signs or symptoms of the condition exist until you are exposed to anesthesia.

Mammary duct ectasia (ek-TAY-zhuh) occurs when a milk duct beneath your nipple widens, the duct walls thicken and the duct fills with fluid. The milk duct may become blocked or clogged with a thick, sticky substance. The condition often causes no symptoms, but some women may have nipple discharge, breast tenderness or inflammation of the clogged duct (periductal mastitis).

Mammary duct ectasia most often occurs in women of perimenopausal age — around 45 to 55 years — but it can happen after menopause, too. The condition sometimes improves without treatment. If symptoms persist, you may need antibiotics or possibly surgery to remove the affected milk duct.Though it's normal to worry about any changes in your breasts, mammary duct ectasia and periductal mastisis aren't risk factors for breast cancer

MEdulloblastoma is a cancerous tumor—also called cerebellar primitive neuroectodermal tumor (PNET)—that starts in the region of the brain at the base of the skull, called the posterior fossa. These tumors tend to spread to other parts of the brain and to the spinal cord

Membranous nephropathy (MEM-bruh-nus nuh-FROP-uh-thee) occurs when the small blood vessels in the kidney (glomeruli), which filter wastes from the blood, become damaged and thickened. As a result, proteins leak from the damaged blood vessels into the urine (proteinuria). For many, loss of these proteins eventually causes signs and symptoms known as nephrotic syndrome.In mild cases, membranous nephropathy may get better on its own, without any treatment. As protein leakage increases, so does the risk of long-term kidney damage. In many, the disease ultimately leads to kidney failure. There's no absolute cure for membranous nephropathy, but successful treatment can lead to remission of proteinuria and a good long-term outlook.

A meningioma is a tumor that arises from the meninges — the membranes that surround your brain and spinal cord. Although not technically a brain tumor, it is included in this category because it may compress or squeeze the adjacent brain, nerves and vessels. Meningioma is the most common type of tumor that forms in the head.

Most meningiomas grow very slowly, often over many years without causing symptoms. But in some instances, their effects on adjacent brain tissue, nerves or vessels may cause serious disability.

Meningiomas occur most commonly in women, and are often discovered at older ages, but a meningioma may occur at any age.

Because most meningiomas grow slowly, often without any significant signs and symptoms, they do not always require immediate treatment and may be monitored over time.

Mental illness refers to a wide range of mental health conditions — disorders that affect your mood, thinking and behavior. Examples of mental illness include depression, anxiety disorders, schizophrenia, eating disorders and addictive behaviors.

Many people have mental health concerns from time to time. But a mental health concern becomes a mental illness when ongoing signs and symptoms cause frequent stress and affect your ability to function.

A mental illness can make you miserable and can cause problems in your daily life, such as at school or work or in relationships. In most cases, symptoms can be managed with a combination of medications and talk therapy (psychotherapy).

Meralgia paresthetica is a condition characterized by tingling, numbness and burning pain in your outer thigh. The cause of meralgia paresthetica is compression of the nerve that supplies sensation to the skin surface of your thigh.

Tight clothing, obesity or weight gain, and pregnancy are common causes of meralgia paresthetica. However, meralgia paresthetica can also be due to local trauma or a disease, such as diabetes.

In most cases, you can relieve meralgia paresthetica with conservative measures, such as wearing looser clothing. In severe cases, treatment may include medications to relieve discomfort or, rarely, surgery.

Mesenteric ischemia (mez-un-TER-ik is-KEE-me-uh) is a condition caused by poor blood supply to your intestines. Mesenteric ischemia usually affects the small intestine, colon or both. It may also involve other organs in the digestive system. Mesenteric ischemia may be acute or chronic.Acute mesenteric ischemia occurs suddenly as a result of blockage to the flow of oxygen-rich blood and can permanently damage your intestines. You may experience sudden abdominal pain and, less often, bloody stools. This situation requires immediate medical care.

Chronic mesenteric ischemia occurs gradually from narrowing in one or more of the arteries supplying blood to your intestines (visceral arteries). You may develop pain 1 to 2 hours after eating, This pain may make it hard for you to eat, leading to weight loss. You may also notice changes in the frequency of your bowel movements, as well as bloating, nausea and vomiting.

Lymphadenitis is a condition in which your lymph nodes become inflamed. When the condition affects the lymph nodes in the membrane that connects your bowel to the abdominal wall (mesentery), it's called mesenteric lymphadenitis (mez-un-TER-ik lim-fad-uh-NIE-tis).Mesenteric lymphadenitis, which is also called mesenteric adenitis, usually results from an intestinal infection. It mainly affects children and teens. This painful condition can mimic the warning signs of appendicitis. Unlike appendicitis, mesenteric lymphadenitis is seldom serious and usually clears up on its own

Malignant mesothelioma (me-zoe-thee-lee-O-muh) is a type of cancer that occurs in the thin layer of tissue that covers the majority of your internal organs (mesothelium).Mesothelioma is an aggressive and deadly form of cancer. Mesothelioma treatments are available, but for many people with mesothelioma, a cure is not possible.Doctors divide mesothelioma into different types based on what part of the mesothelium is affected. Mesothelioma most often affects the tissue that surrounds the lungs (pleura). This type is called pleural mesothelioma. Other, rarer types of mesothelioma affect tissue in the abdomen (peritoneal mesothelioma), around the heart and around the testicles.Mesothelioma doesn't include a form of noncancerous (benign) tumor that occurs in the chest and is sometimes called benign mesothelioma or solitary fibrous tumor.

Does your hair feel brittle and stiff? Dyeing, bleaching, straightening or blowing out your hair a lot can damage it over time. These processes dry out your hair and leave it prone to breakage and split ends. Once your hair is damaged, the best way to restore it is to give it time to grow back in healthy and strong. Use deep conditioning treatments to help bring back its luster, and be healthy from the inside out to promote the growth of new healthy hair.

Metatarsalgia (met-uh-tahr-SAL-juh) is a condition in which the ball of your foot becomes painful and inflamed. You might develop it if you participate in activities that involve running and jumping. There are other causes as well, including foot deformities and shoes that are too tight or too loose.Although generally not serious, metatarsalgia can sideline you. Fortunately, at-home treatments, such as ice and rest, often relieve symptoms. Wearing proper footwear with shock-absorbing insoles or arch supports might prevent or minimize future problems with metatarsalgia.

Microcephaly (my-kroh-SEF-uh-lee) is a rare neurological condition in which an infant's head is significantly smaller than the heads of other children of the same age and sex. Sometimes detected at birth, microcephaly usually is the result of the brain developing abnormally in the womb or not growing as it should after birth.Microcephaly can be caused by a variety of genetic and environmental factors. Children with microcephaly often have developmental issues. Generally there's no treatment for microcephaly, but early intervention with supportive therapies, such as speech and occupational therapies, may help enhance your child's development and improve quality of life.

Migraine with aura (also called classic migraine) is a headache that strikes after or along with sensory disturbances called aura. These disturbances can include flashes of light, blind spots and other vision changes or tingling in your hand or face.Treatments for migraine with aura and migraine without aura (also called common migraine) are usually the same. You can try to prevent migraine with aura with the same medications and self-care measures used to prevent migraine.

Between 2 and 3 percent of children younger than 3 are allergic to milk. Although experts once believed that the vast majority of them would outgrow this allergy by the time they turned 3, recent studies contradict this theory. In one study, fewer than 20 percent of children had outgrown their allergy by age 4. Still, about 80 percent of children are likely to outgrow their milk allergy before they are 16.

Mitral valve prolapse (MVP) occurs when the leaflets of the mitral valve bulge (prolapse) into the heart's left upper chamber (left atrium) like a parachute during the heart's contraction.Mitral (MY-trul) valve prolapse sometimes leads to blood leaking backward into the left atrium, a condition called mitral valve regurgitation.in most people, mitral valve prolapse isn't life-threatening and doesn't require treatment or changes in lifestyle. Some people with mitral valve prolapse, however, require treatment.

Mitral valve stenosis — or mitral stenosis — is a narrowing of the heart's mitral valve. This abnormal valve doesn't open properly, blocking blood flow into the main pumping chamber of your heart (left ventricle). Mitral valve stenosis can make you tired and short of breath, among other problems.The main cause of mitral valve stenosis is an infection called rheumatic fever, which is related to strep infections. Rheumatic fever — now rare in the United States, but still common in developing countries — can scar the mitral valve. Left untreated, mitral valve stenosis can lead to serious heart complications.

Mittelschmerz is one-sided, lower abdominal pain associated with ovulation. German for "middle pain," mittelschmerz occurs midway through a menstrual cycle — about 14 days before your next menstrual period.In most cases, mittelschmerz doesn't require medical attention. For minor mittelschmerz discomfort, over-the-counter pain relievers and home remedies are often effective. If your mittelschmerz pain is troublesome, your doctor may prescribe an oral contraceptive to stop ovulation and prevent midcycle pain.

• A molar pregnancy is the result of a genetic error during the fertilization process that leads to a growth of abnormal tissue within the uterus. Molar pregnancies rarely involve a developing embryo, and the growth of this material is rapid compared to normal fetal growth. It has the appearance of a large and random collection of grape-like cell clusters. There are two types of molar pregnancies, “complete,” and “partial.”
  

Mold allergies can be tough to outrun. The fungus can grow in your basement, in your bathroom, in the cabinet under your sink where a leak went undetected, in the pile of dead leaves in your backyard and in the field of uncut grass down the road.There are roughly 1,000 species of mold in the United States — many of which aren’t visible to the naked eye. As tiny mold spores become airborne, they can cause allergic reactions in people who have mold allergies.

Infectious mononucleosis (mono) is often called the kissing disease. The virus that causes mono is transmitted through saliva, so you can get it through kissing, but you can also be exposed through a cough or sneeze, or by sharing a glass or food utensils with someone who has mono. However, mononucleosis isn't as contagious as some infections, such as the common cold.You're most likely to get mononucleosis with all the signs and symptoms if you're an adolescent or young adult. Young children usually have few symptoms, and the infection often goes unrecognized.If you have mononucleosis, it's important to be careful of certain complications such as an enlarged spleen. Rest and adequate fluids are key to recovery.

If you have a mood disorder, your general emotional state or mood is distorted or inconsistent with your circumstances and interferes with your ability to function. You may be extremely sad, empty or irritable (depressed), or you may have periods of depression alternating with being excessively happy (mania).Anxiety disorders can also affect your mood and often occur along with depression. Mood disorders may increase your risk of suicide.

Morphea (mor-FEE-uh) is a rare skin condition that causes painless, discolored patches on your skin.Typically, the skin changes appear on the abdomen, chest or back. But they might also appear on your face, arms or legs. Morphea tends to affect only the outermost layers of your skin. But some forms of the condition also restrict movement in the joints.Morphea usually subsides on its own over time, though recurrences are common. In the meantime, medications and therapies are available to help treat the skin discoloration and other effects

Mouth cancer, also known as oral cancer, is where a tumour develops in the lining of the mouth. It may be on the surface of the tongue, the insides of the cheeks, the roof of the mouth (palate), or the lips or gums.Tumours can also develop in the glands that produce saliva, the tonsils at the back of the mouth, and the part of the throat connecting your mouth to your windpipe (pharynx). However, these are less common.

Movement disorders are clinical syndromes with either an excess of movement or a paucity of voluntary and involuntary movements, unrelated to weakness or spasticity.[1] Movement disorders are synonymous with basal ganglia or extrapyramidal diseases.[2] Movement disorders are conventionally divided into two major categories- hyperkinetic and hypokinetic.Hyperkinetic movement disorders refer to dyskinesia, or excessive, often repetitive, involuntary movements that intrude upon the normal flow of motor activity.Hypokinetic movement disorders refer to akinesia (lack of movement), hypokinesia (reduced amplitude of movements), bradykinesia (slow movement) and rigidity. In primary movement disorders, the abnormal movement is the primary manifestation of the disorder. In secondary movement disorders, the abnormal movement is a manifestation of another systemic or neurological disorde

Moyamoya disease is a rare, progressive cerebrovascular disorder caused by blocked arteries at the base of the brain in an area called the basal ganglia. The name “moyamoya” means “puff of smoke” in Japanese and describes the look of the tangle of tiny vessels formed to compensate for the blockage.  Moyamoya disease was first described in Japan in the 1960s and it has since been found in individuals in the other countries around the world; its incidence is higher in Asian countries than in Europe or North America. The disease primarily affects children, but it can also occur in adults. In children, the first symptom of Moyamoya disease is often stroke, or recurrent transient ischemic attacks (TIA, commonly referred to as “mini-strokes”), frequently accompanied by muscular weakness or paralysis affecting one side of the body, or seizures.  Adults may also experience these symptoms that arise from blocked arteries, but more often experience a hemorrhagic stroke due to bleeding into the brain from the abnormal brain vessels.  Individuals with this disorder may have disturbed consciousness, problems with speaking and understanding speech, sensory and cognitive impairments, involuntary movements, and vision problems. About one in 10 individuals with Moyamoya disease has a close relative who is also affected; in these cases researchers think that Moyamoya disease is the result of inherited genetic abnormalities. Studies that look for the abnormal gene(s) may help reveal the biomechanisms that cause the disorder.

Staphylococcus aureus (SA) is a common skin bacteria. It is sometimes called staph, and it most often causes skin and soft tissue infections. Although S. aureus has been causing staph infections as long as humans have existed, MRSA has only been around since 1961. Methicillin was one of the first antibiotics used to treat S. aureus and other infections. S. aureus developed a gene mutation that allowed it to escape being killed by methicillin, so it became resistant to methicillin. That makes it harder to treat someone who gets an infection. Stronger, more expensive, or intravenous antibiotics may be needed.

Since the 1960s, MRSA has picked up more resistance to different antibiotics. Overuse of antibiotics has increased resistance in MRSA and other infectious bacteria, because resistance genes (the genes that code for resistance) can be passed from bacteria to bacteria.

If a doctor orders a test for bacteria on a specimen of pus, for example, the laboratory will alert the doctor if the test shows MRSA, so that precautions can be taken, and the right treatment can be started.

Multiple myeloma is a cancer that forms in a type of white blood cell called a plasma cell. Plasma cells help you fight infections by making antibodies that recognize and attack germs.Multiple myeloma causes cancer cells to accumulate in the bone marrow, where they crowd out healthy blood cells. Rather than produce helpful antibodies, the cancer cells produce abnormal proteins that can cause complications.Treatment for multiple myeloma isn't always necessary for people who aren't experiencing any signs or symptoms. For people with multiple myeloma who require treatment, a number of treatments are available to help control the disease.

Multiple sclerosis (MS) is a potentially disabling disease of the brain and spinal cord (central nervous system).In MS, the immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between your brain and the rest of your body. Eventually, the disease can cause the nerves themselves to deteriorate or become permanently damaged.Signs and symptoms of MS vary widely and depend on the amount of nerve damage and which nerves are affected. Some people with severe MS may lose the ability to walk independently or at all, while others may experience long periods of remission without any new symptoms.There's no cure for multiple sclerosis. However, treatments can help speed recovery from attacks, modify the course of the disease and manage symptoms.

Even some of the most stunning women often have to resort to concealers and make-up to hide their dark circles. Not only do these under-eye circles make you look much older than what you actually are, but they also have you looking ill or unhealthy.

Before we even begin this natural journey, let me tell you that dark circles take time to cure and require great discipline. A regular skin and health care program should be followed, by the book, so do not expect magic to happen overnight.

Myasthenia gravis (my-us-THEE-nee-uh GRAY-vis) is characterized by weakness and rapid fatigue of any of the muscles under your voluntary control.Myasthenia gravis is caused by a breakdown in the normal communication between nerves and muscles.There is no cure for myasthenia gravis, but treatment can help relieve signs and symptoms, such as weakness of arm or leg muscles, double vision, drooping eyelids, and difficulties with speech, chewing, swallowing and breathing.Though myasthenia gravis can affect people of any age, it's more common in women younger than 40 and in men older than 60.

Myelodysplastic syndromes are a group of disorders caused by poorly formed blood cells or ones that don't work properly. Myelodysplastic syndromes result from something amiss in the spongy material inside your bones where blood cells are made (bone marrow).Treatment for myelodysplastic syndromes usually focuses on reducing or preventing complications of the disease and its treatments. In some cases, treatment might involve chemotherapy or a bone marrow transplant.

Myelofibrosis is a serious bone marrow disorder that disrupts your body's normal production of blood cells. The result is extensive scarring in your bone marrow, leading to severe anemia, weakness, fatigue and often an enlarged spleen.Myelofibrosis is an uncommon type of chronic leukemia — a cancer that affects the blood-forming tissues in the body. Myelofibrosis belongs to a group of diseases called myeloproliferative disorders.Many people with myelofibrosis get progressively worse, and some may eventually develop a more serious form of leukemia. Yet it's also possible to have myelofibrosis and live symptom-free for years. Treatment for myelofibrosis, which focuses on relieving symptoms, can involve a variety of options.

Myocardial ischemia occurs when blood flow to your heart is reduced, preventing it from receiving enough oxygen. The reduced blood flow is usually the result of a partial or complete blockage of your heart's arteries (coronary arteries).Myocardial ischemia, also called cardiac ischemia, can damage your heart muscle, reducing its ability to pump efficiently. A sudden, severe blockage of a coronary artery can lead to a heart attack. Myocardial ischemia might also cause serious abnormal heart rhythms.Treatment for myocardial ischemia involves improving blood flow to the heart muscle. Treatment may include medications, a procedure to open blocked arteries or bypass surgery.Making heart-healthy lifestyle choices is important in treating and preventing myocardial ischemia.

Myofascial pain syndrome (MPS) refers to pain and presumed inflammation in the body's soft tissues or muscles. Myofascial pain is a chronic, painful condition that affects the fascia (connective tissue that covers the muscles). Myofascial pain syndrome might involve either a single muscle or a muscle group. In some cases, the area where a person experiences the pain might not be where the myofascial pain generator is located. Experts believe that the actual site of the injury or the strain prompts the development of a trigger point that, in turn, causes pain in other areas. This situation is known as referred pain.

Naegleria (nay-GLEER-e-uh) infection is a rare and usually fatal brain infection caused by an amoeba commonly found in freshwater lakes, rivers and hot springs. Exposure occurs during swimming or other water sports.The amoeba — called Naegleria fowleri — travels up the nose to the brain, where it causes severe damage. Most people who have naegleria infection die within a week.Millions of people are exposed to the amoeba that causes naegleria infection each year, but only a handful of them ever get sick from it. Health officials don't know why some people develop naegleria infection while others don't.Avoiding warm bodies of fresh water and wearing nose clips while in the water may help prevent such infections.

Even some of the most stunning women often have to resort to concealers and make-up to hide their dark circles. Not only do these under-eye circles make you look much older than what you actually are, but they also have you looking ill or unhealthy.Before we even begin this natural journey, let me tell you that dark circles take time to cure and require great discipline. A regular skin and health care program should be followed, by the book, so do not expect magic to happen overnight.

Nasopharyngeal (nay-zoh-fuh-RIN-jee-ul) carcinoma is cancer that occurs in the nasopharynx, which is located behind your nose and above the back of your throat.Nasopharyngeal carcinoma is rare in the United States. In other parts of the world — specifically Southeast Asia — nasopharyngeal carcinoma occurs much more frequently.Nasopharyngeal carcinoma is difficult to detect early. That's probably because the nasopharynx isn't easy to examine and symptoms of nasopharyngeal carcinoma mimic those of other, more-common conditions.Treatment for nasopharyngeal carcinoma usually involves radiation therapy, chemotherapy or a combination of the two. You can work with your doctor to determine the exact approach depending on your particular situation

Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry.Nearsightedness may develop gradually or rapidly, often worsening during childhood and adolescence. Nearsightedness tends to run in families.A basic eye exam can confirm nearsightedness. You can easily correct the condition with eyeglasses or contact lenses. Another treatment option for nearsightedness is surgery.

Nephrotic syndrome is a kidney disorder that causes your body to excrete too much protein in your urine.Nephrotic syndrome is usually caused by damage to the clusters of small blood vessels in your kidneys that filter waste and excess water from your blood. Nephrotic syndrome causes swelling (edema), particularly in your feet and ankles, and increases the risk of other health problems.Treatment for nephrotic syndrome includes treating the underlying condition that's causing it and taking medications. Nephrotic syndrome can increase your risk of infections and blood clots. Your doctor may recommend medications and dietary changes to prevent these and other complications of nephrotic syndrome.

Neurodermatitis is a skin condition that begins with an itch.The itch can develop anywhere on the surface of the body. Most commonly, though, an itchy patch develops on an arm, leg, or the back of the neck. It also commonly develops in the anal and genital areas. When it appears in the genital area, it often appears on the scrotum or vulva.The itch can be so intense that a person scratches or rubs the itchy patch frequently. The itch can also come and go. For most people, the area feels itchiest when they are relaxing or sleeping. The itch causes people to scratch or rub the area while sleeping — and it can awaken someone from a sound sleep.Quite often, the itch begins during an especially stressful time in someone’s life. Even when the stress subsides, the itch usually continues. Scratching or rubbing can change the appearance of that itchy patch.

Neuroendocrine tumors are abnormal growths that begin in specialized cells called neuroendocrine cells. Neuroendocrine cells have traits similar to nerve cells and to hormone-producing cells.Neuroendocrine tumors are rare and can occur anywhere in the body. Most neuroendocrine tumors occur in the lungs, appendix, small intestine, rectum and pancreas.Neuroendocrine tumors can be noncancerous (benign) or cancerous (malignant).Diagnosis and treatment of neuroendocrine tumors depend on the type of tumor, its location, whether it produces excess hormones, how aggressive it is and whether it has spread to other parts of the body

Neurofibromatosis is a genetic disorder that causes tumors to form on nerve tissue. These tumors can develop anywhere in your nervous system, including your brain, spinal cord and nerves. Neurofibromatosis is usually diagnosed in childhood or early adulthood.The tumors are usually noncancerous (benign), but sometimes can become cancerous (malignant). Symptoms are often mild. However, complications of neurofibromatosis can include hearing loss, learning impairment, heart and blood vessel (cardiovascular) problems, loss of vision, and severe pain.Neurofibromatosis treatment aims to maximize healthy growth and development and to manage complications as soon as they arise. When neurofibromatosis causes large tumors or tumors that press on a nerve, surgery can help ease symptoms. Some people may benefit from other therapies, such as stereotactic radiosurgery or medications to control pain.

Your doctor can usually diagnose nickel allergy based on your skin's appearance, and a recent exposure to items that may contain nickel.If the cause of your rash isn't apparent, however, your doctor may recommend a patch test (contact hypersensitivity allergy test). He or she may refer you to an allergy specialist (allergist) or a skin specialist (dermatologist) for this test.

Nicotine dependence ― also called tobacco dependence ― is an addiction to tobacco products caused by the drug nicotine. Nicotine dependence means you can't stop using the substance, even though it's causing you harm.Nicotine produces physical and mood-altering effects in your brain that are temporarily pleasing. These effects make you want to use tobacco and lead to dependence. At the same time, stopping tobacco use causes withdrawal symptoms, including irritability and anxiety.While it's the nicotine in tobacco that causes nicotine dependence, the toxic effects of tobacco result from other substances in tobacco. Smokers have much higher rates of heart disease, stroke and cancer than nonsmokers do.Regardless of how long you've smoked, stopping smoking can improve your health. Many effective treatments for nicotine dependence are available to help you manage withdrawal and stop smoking for good. Ask your doctor for hel

Niemann-Pick is a rare, inherited disease that affects the body's ability to metabolize fat (cholesterol and lipids) within cells. These cells malfunction and, over time, die. Niemann-Pick disease can affect the brain, nerves, liver, spleen, bone marrow and, in severe cases, lungs.People with this condition experience symptoms related to progressive loss of function of nerves, the brain and other organs.Niemann-Pick can occur at any age but mainly affects children. The disease has no known cure and is sometimes fatal. Treatment is focused on helping people live with their symptoms.

A nightmare is a disturbing dream associated with negative feelings, such as anxiety or fear that awakens you. Nightmares are common in children, but can happen at any age, and occasional nightmares usually are nothing to worry about.Nightmares may begin in children between 3 and 6 years old and tend to decrease after the age of 10. During the teen and young adult years, girls appear to have nightmares more often than boys do. Some people have them as adults or throughout their lives.Although nightmares are common, nightmare disorder is relatively rare. Nightmare disorder is when nightmares happen often, cause distress, disrupt sleep, cause problems with daytime functioning or create fear of going to sleep.

Have you ever noticed how the skin on your elbows and knees is often darker than the rest of the skin on your arms and legs? It's a bit funny-looking, isn't it? Some people think it's the result of dirt (and sometimes it is), but you'd be surprised to find that dirt often has nothing to do with the dark spots on your elbows and knees.

Nonallergic rhinitis with eosinophilia syndrome (NARES) is a clinical syndrome comprising symptoms consistent with allergic rhinitis in which an absence of atopy has been demonstrated by allergen skin testing, and nasal cytology analysis demonstrates more than 20% eosinophils. Anosmia is a prominent feature not shared with allergic rhinitis. The pathophysiology of NARES is poorly understood, but a key component involves a self-perpetuating, chronic eosinophilic nasal inflammation with development of nasal micropolyposis and polyposis. Mast cells likely play an important role as well. NARES is a risk factor for the development of nasal polyposis and aspirin sensitivity, as well as obstructive sleep apnea. Treatment consists mainly of intranasal corticosteroids with or without the addition of second-generation antihistamines and/or leukotriene-receptor antagonists.

Nonulcer stomach pain is a term for recurring signs and symptoms of indigestion that have no obvious cause. Nonulcer stomach pain is also called functional dyspepsia (dis-PEP-see-uh) or nonulcer dyspepsia.Nonulcer stomach pain is common and can be long lasting. The condition can cause signs and symptoms that resemble those of an ulcer, such as pain or discomfort in your upper abdomen, often accompanied by bloating, belching and nausea.

Noonan syndrome is a genetic disorder that prevents normal development in various parts of the body. A person can be affected by Noonan syndrome in a wide variety of ways. These include unusual facial characteristics, short stature, heart defects, other physical problems and possible developmental delays.Noonan syndrome is caused by a genetic mutation and is acquired when a child inherits a copy of an affected gene from a parent (dominant inheritance). It can also occur as a spontaneous mutation, meaning there's no family history involved.Management of Noonan syndrome focuses on controlling the disorder's symptoms and complications. Growth hormone may be used to treat short stature in some people with Noonan syndrome.

Norovirus infection can cause the sudden onset of severe vomiting and diarrhea. The virus is highly contagious and commonly spread through food or water that is contaminated during preparation or contaminated surfaces. You can also be infected through close contact with an infected person.Diarrhea, abdominal pain and vomiting typically begin 12 to 48 hours after exposure. Norovirus symptoms last one to three days, and most people recover completely without treatment. However, for some people — especially infants, older adults and people with underlying disease — vomiting and diarrhea can be severely dehydrating and require medical attention.Norovirus infection occurs most frequently in closed and crowded environments such as hospitals, nursing homes, child care centers, schools and cruise ships.

Ocular rosacea is inflammation that causes redness, burning and itching of the eyes. It often develops in people who have rosacea, a chronic skin condition that affects the face. Sometimes ocular, or eye, rosacea is the first sign that you may later develop the facial type.Ocular rosacea (roe-ZAY-she-uh) primarily affects adults between the ages of 30 and 50. It seems to develop in people who tend to blush and flush easily.Medications and a good eye-care routine can help control the signs and symptoms. But treatment doesn't cure ocular rosacea. It often recurs after an apparent remission.

Oligodendrogliomas are generally soft, grayish-pink tumors. They often contain mineral deposits (called calcifications), areas of hemorrhage, and/or cysts. Under the microscope, these tumor cells appear to have “short arms,” or a fried-egg shape.

Sometimes oligodendrogliomas are mixed with other cell types. These tumors may be graded using an “A to D” system, which is based on microscopic features of the individual tumor cells. The grade indicates how quickly the tumor cells reproduce and how aggressive the tumor is.

Optic neuritis is an inflammation that damages the optic nerve, a bundle of nerve fibers that transmits visual information from your eye to your brain. Pain and temporary vision loss in one eye are common symptoms of optic neuritis.

Optic neuritis is linked to multiple sclerosis (MS), a disease that causes inflammation and damage to nerves in your brain and spinal cord. Signs and symptoms of optic neuritis can be the first indication of multiple sclerosis, or they can occur later in the course of MS. Besides MS, optic neuritis can occur with other infections or immune diseases, such as lupus.

Most people who have a single episode of optic neuritis eventually recover their vision. Treatment with steroid medications may speed up vision recovery after optic neuritis.

Lichen planus is an itchy skin rash that is caused by an immune response. It can occur anywhere on your skin.oral lichen planusIn cases of oral lichen planus, the mucous membranes inside your mouth are the only area affected. Oral lichen planus presents symptoms different from other cases of lichen planus. Instead of a rash, people may experience swollen tissues, white patches, and open sores.Oral lichen planus isn’t contagious, and it can’t be spread to another person.

The bones of children and adolescents possess a special area where the bone is growing called the growth plate. Growth plates are areas of cartilage located near the ends of bones. When a child is fully grown, the growth plates harden into solid bone.Some growth plates serve as attachment sites for tendons, the strong tissues that connect muscles to bones. A bony bump called the tibial tubercle covers the growth plate at the end of the tibia. The group of muscles in the front of the thigh (called the quadriceps) attaches to the tibial tubercle.When a child is active, the quadriceps muscles pull on the patellar tendon which in turn, pulls on the tibial tubercle. In some children, this repetitive traction on the tubercle leads to inflammation of the growth plate. The prominence, or bump, of the tibial tubercle may become very pronounced.

Osteochondritis dissecans (OCD) is a condition that develops in joints, most often in children and adolescents. It occurs when a small segment of bone begins to separate from its surrounding region due to a lack of blood supply. As a result, the small piece of bone and the cartilage covering it begin to crack and loosen.The most common joints affected by osteochondritis dissecans are the knee, ankle and elbow, although it can also occur in other joints. The condition typically affects just one joint, however, some children can develop OCD in several joints.In many cases of OCD in children, the affected bone and cartilage heal on their own, especially if a child is still growing. In grown children and young adults, OCD can have more severe effects. The OCD lesions have a greater chance of separating from the surrounding bone and cartilage, and can even detach and float around inside the joint. In these cases, surgery may be necessary.

Osteomyelitis is an infection of the bone, a rare but serious condition. Bones can become infected in a number of ways: Infection in one part of the body may spread through the bloodstream into the bone, or an open fracture or surgery may expose the bone to infection.

Osteosarcoma is the most common type of cancer that develops in bone. Like the osteoblasts in normal bone, the cells that form this cancer make bone matrix. But the bone matrix of an osteosarcoma is not as strong as that of normal bones.Most osteosarcomas occur in children and young adults. Teens are the most commonly affected age group, but osteosarcoma can occur at any ageIn children and young adults, osteosarcoma usually develops in areas where the bone is growing quickly, such as near the ends of the long bones. Most tumors develop in the bones around the knee, either in the distal femur (the lower part of the thigh bone) or the proximal tibia (the upper part of the shinbone). The proximal humerus (the part of the upper arm bone close to the shoulder) is the next most common site. However, osteosarcoma can develop in any bone, including the bones of the pelvis (hips), shoulder, and jaw. This is especially true in older adults.

Pancreatic cysts are collections (pools) of fluid that can form within the head, body, and tail of the pancreas. Some pancreatic cysts are true cysts (non-inflammatory cysts), that is, they are lined by a special layer of cells that are responsible for secreting fluid into the cysts. Other cysts are pseudocysts (inflammatory cysts) and do not contain specialized lining cells. Often these pseudocysts contain pancreatic digestive juices because they are connected to the pancreatic ducts. Pancreatic cysts can range in size from several millimeters to several centimeters. Many pancreatic cysts are small and benign and produce no symptoms, but some cysts become large and cause symptoms, and others are cancerous or precancerous. (Precancerous cysts are benign cysts that have the potential to become cancerous.)Different types of cysts contain different types of fluids. For example, pseudocysts that form after an attack of acute pancreatitis contain digestive enzymes such as amylase in high concentrations. Mucinous cysts contain mucus (a proteinaceous liquid) produced by the mucinous cells that form the inside lining of the cyst.

Parkinson's disease is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while a tremor may be the most well-known sign of Parkinson's disease, the disorder also commonly causes stiffness or slowing of movement.

In the early stages of Parkinson's disease, your face may show little or no expression, or your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time.

Although Parkinson's disease can't be cured, medications may markedly improve your symptoms. In occasional cases, your doctor may suggest surgery to regulate certain regions of your brain and improve your symptoms.

Black neck is a term used to describe a condition in which the skin on your neck is noticeably darker than the surrounding skin, also referred to as “dark neck.” The change in color may be alarming and make you self-conscience, however, in most cases it isn’t cause for concern nor is it contagious.

In some cases, however, this skin darkening may be a warning sign of something more serious, so it’s important to see a doctor to determine the cause and begin any necessary treatment. Read on to learn more about black neck, what causes it, and how to treat it

Parvovirus infection is a common and highly contagious childhood ailment — sometimes called slapped-cheek disease because of the distinctive face rash that develops. Parvovirus infection has also been known as fifth disease because, historically, it was one of five common childhood illnesses characterized by a rash.In most children, parvovirus infection is mild and requires little treatment. However, in some adults, the infection can be serious. Parvovirus infection in some pregnant women can lead to serious health problems for the fetus. Parvovirus infection is also more serious for people with some kinds of anemia or who have a compromised immune system.

Patellar tendinitis is an injury to the tendon connecting your kneecap (patella) to your shinbone. The patellar tendon works with the muscles at the front of your thigh to extend your knee so you can kick, run and jump.Patellar tendinitis, also known as jumper's knee, is most common in athletes whose sports involve frequent jumping — such as basketball and volleyball. However, even people who don't participate in jumping sports can get patellar tendinitis.For most people, treatment of patellar tendinitis begins with physical therapy to stretch and strengthen the muscles around the knee

A foramen ovale is a hole in the heart. The small hole naturally exists in babies who are still in the womb for fetal circulation. It should close soon after birth. If it doesn’t close, the condition is called patent foramen ovale (PFO).PFOs are common. They occur in roughly one out of every four people. If you have no other heart conditions or complications, treatment for PFO is unnecessary.While a fetus develops in the womb, a small opening exists between the two upper chambers of the heart called the atria. This opening is called the foramen ovale. The purpose of the foramen ovale is to help circulate blood through the heart. A fetus doesn’t use their own lungs to oxygenate their blood. They rely on their mother’s circulation to provide oxygen to their blood from the placenta. The foramen ovale helps blood circulate more quickly in the absence of lung function.When your baby is born and their lungs begin to work, the pressure inside their heart usually causes the foramen ovale to close. Sometimes it may not happen for a year or two. In some people, the closure may never happen at all, resulting in PFO.

Many schools have declared that they are “nut-free,” meaning that the onetime staple of kids’ lunchboxes — a peanut butter and jelly sandwich — is nowhere to be found on school grounds these days. That’s because peanuts can cause a life-threatening reaction in some people. Peanuts are one of the food allergens most commonly associated with anaphylaxis, a sudden and potentially deadly condition that requires immediate attention and treatment.In recent years, awareness about peanut allergy in children has risen, as has the number of peanut allergy cases reported. In May 2010, a study noted that the rate of peanut allergies in children, as reported in a telephone survey, had more than tripled between 1997 and 2008.There are several misconceptions about peanut allergies. A peanut is a legume (belonging to the same family as soybeans, peas and lentils), not a tree nut. And while it was previously believed that an allergy to peanuts was lifelong, research by the National Institutes of Health shows that about 20 percent of individuals with a peanut allergy eventually outgrow it.

Pectus carinatum, sometimes called pigeon chest, is a non-life-threatening condition. It’s marked by an abnormally outward protruding breastbone caused by rapid cartilage growth forcing the chest cavity outward. Occasionally, symptoms are present from birth or early childhood, but it’s most commonly diagnosed around 11 or 12 years of age.For most children, pectus carinatum is an aesthetic issue only. This condition frequently results in an asymmetrical chest. In more severe cases, symptoms may also include difficulty breathing during physical activities, recurring respiratory infections, and asthma.While its cause is unknown, it appears to be more common in boys, and there seems to be a hereditary component. If needed, treatment for pectus carinatum usually includes wearing a brace for children whose bones are still developing. But it can also include surgery for severe cases.

Pectus excavatum is a condition in which a person's breastbone is sunken into his or her chest. In severe cases, pectus excavatum can look as if the center of the chest has been scooped out, leaving a deep dent.While the sunken breastbone is often noticeable shortly after birth, the severity of pectus excavatum typically worsens during the adolescent growth spurt.Also called funnel chest, pectus excavatum is more common in boys than in girls. Severe cases of pectus excavatum can eventually interfere with the function of the heart and lungs. But even mild cases of pectus excavatum can make children feel self-conscious about their appearance. Surgery can correct the deformity.

Pediatric brain tumors are masses or growths of abnormal cells that occur in a child's brain or the tissue and structures that are near it. Many different types of pediatric brain tumors exist — some are noncancerous (benign) and some are cancerous (malignant).Treatment and chance of recovery (prognosis) depend on the type of tumor, its location within the brain, whether it has spread, and your child's age and general health. Because new treatments and technologies are continually being developed, several options may be available at different points in treatment.Treatment for brain tumors in children is typically quite different from treatment for adult brain tumors, so it's very important to enlist the expertise and experience of pediatric specialists in neurology and cancer.

Pemphigus is a group of rare skin disorders that cause blisters and sores on the skin or mucous membranes, such as in the mouth or on the genitals.The two main types are pemphigus vulgaris and pemphigus foliaceus. Pemphigus vulgaris usually starts in your mouth. It can be painful. Pemphigus foliaceus affects the skin and tends to be more itchy than painful. Pemphigus can occur at any age, but it's most often seen in people who are middle-aged or older.Pemphigus is not to be confused with bullous pemphigoid, another blistering skin condition. Usually a chronic condition, pemphigus is best controlled by early diagnosis and treatment. Treatment may include medications and therapies similar to those used for severe burns

Penicillin allergy is an abnormal reaction of your immune system to the antibiotic drug penicillin. Penicillin is prescribed for treating various bacterial infections.

Common signs and symptoms of penicillin allergy include hives, rash and itching. Severe reactions include anaphylaxis, a life-threatening condition that affects multiple body systems.

Research has shown that penicillin allergies may be over-reported — a problem that can result in the use of less appropriate and more expensive antibiotic treatments. Therefore, an accurate diagnosis is needed when penicillin allergy is suspected to ensure the best treatment options in the future.

Other antibiotics, particularly those with chemical properties similar to penicillin, can also result in allergic reactions.

An “ulcer” is an open sore. The word “peptic” means that the cause of the problem is due to acid. Most of the time when a gastroenterologist is referring to an “ulcer” the doctor means a peptic ulcer.The two most common types of peptic ulcer are called “gastric ulcers” and “duodenal ulcers”. These names refer to the location where the ulcer is found. Gastric ulcers are located in the stomach (see Figure 1). Duodenal ulcers are found at the beginning of the small intestine (also called the small bowel) known as the duodenum. A person may have both gastric and duodenal ulcers at the same time.

Dark underarms can be defined as the dark coloration of skin in the underarm region compared to the rest of the body. It is a problem many individuals find embarrassing. Ascertaining the reason can help to alleviate the problem effectively.