- Small, painful, fluid-filled blisters on a raised, red, painful area of your skin
- Pain or tingling, called the prodrome, often precedes the blisters by one to two days
- Usual duration of seven to 10 days
Cold sores usually appear on your lips. Occasionally, they occur on your nostrils, chin or fingers. And, although it's unusual, they may occur inside your mouth but only on your gums or hard palate, which is the roof of your mouth. If the sore appears on other soft tissues inside your mouth, it may be a canker sore, but it's not a cold sore.
Signs and symptoms may not start for as long as 20 days after exposure to the herpes simplex virus, and usually last seven to 10 days. The blisters form, break and ooze. Then a yellow crust forms and finally sloughs off to uncover pinkish skin that heals without a scar.
Causes
Certain strains of the herpes virus cause cold sores. Herpes simplex virus type 1 usually causes cold sores. Herpes simplex virus type 2 is usually responsible for genital herpes. However, either type of the virus can cause sores in the facial area or on the genitals. You get cold sores from another person who has an active lesion. Shared eating utensils, razors and towels may spread this infection.
Once you've had an episode of cold sores, the virus lies dormant in the nerve cells in your skin and may emerge again as an active infection at or near the original site. You may experience an itch or heightened sensitivity at the site preceding each attack. Fever, menstruation, stress and exposure to the sun may trigger a recurrence.
When to seek medical advice.
Cold sores generally clear up on their own without treatment. However, see your doctor if :
- You have a pre-existing health condition that has compromised your immune system
- The cold sores don't heal within one to two weeks on their own
- Symptoms are severe
- You have frequent recurrences of cold sores
- You experience irritation in your eyes
