Many people have the herpes simplex virus but no symptoms. They will only know they are infected if cold sores appear.
The first time a cold sore appears, as part of a primary infection, it may be severe.
After this, cold sores are considered a symptom of HSV-1 and 2. They remain as the only recurring sign that the virus is present in the body.
In most cases, there are no other detectable signs or symptoms of a herpes infection.
Severe symptoms are more likely to affect young children, as they have not yet had time to build up antibodies as a defense.
Symptoms can include:
lesions, blisters, or ulcers on the tongue or mouth
mouth or tongue pain
lip swelling
possible swallowing difficulties
sore throat
swollen glands
high body temperature
dehydration
nausea
headaches
There may also be an infection of the mouth and gums, known as gingivostomatitis. This lasts for 1 to 2 weeks, and it does not recur.
Pharyngotonsillitis, an infection of the throat and tonsils, may occur when the primary infection affects adults.
A cold sore will develop in several stages when it recurs.
A tingling, itching or burning sensation around the mouth often indicates the start of a cold-sore outbreak. Fluid-filled sores, often on the edges of the lower lip, tend to follow this. Glands may start to swell.
The sores often appear in the same place each time. Pain and irritation develop alongside the cold sore.
The sores break and ooze.
A yellow crust forms on top of the sores and scabs off to uncover pink skin that heals without scarring.
Most cold sores disappear within a week or two.