Also called: Fever Blisters

What Are Cold Sores?

Cold sores are small painful blisters that form on or near the lips or nose. Cold sores are common and tend to go away on their own within 1 to 2 weeks.

What Are the Signs & Symptoms of Cold Sores?

The first signs of cold sores are often tingling and numbness around the mouth before blisters form. The blisters are filled with fluid. When they break, they become sores, which can make eating painful. The sores crust over and form a scab before they go away.

Cold sores also can cause red and swollen gums, a fever, muscle aches, a generally ill feeling, and swollen neck glands.

What Causes Cold Sores?

The herpes simplex virus type 1 (HSV-1) causes cold sores. It's contagious and spreads easily from one person to another. This isn't the same virus as HSV type 2 (HSV-2), which causes sores in the genital area (genital herpes). But even though HSV-1 typically causes sores around the mouth and HSV-2 causes most genital sores, both viruses can cause sores in either body area.

After someone has had cold sores, the virus can quietly stay in their body for a long time without causing symptoms. Later, symptoms can happen again because of things like:

• other infections
• a fever
• sunlight
• cold weather
• periods
• stress, like before a big test at school

How Do People Get Cold Sores?

People can get HSV-1 by kissing or touching someone with cold sores or by sharing eating utensils (like forks, spoons, and chopsticks), towels, or other items with a person who has the virus. Many people with HSV-1 got it as kids during their preschool years (ages 3–5).

How Are Cold Sores Treated?

Cold sores usually go away in about 1–2 weeks. No medicines can kill the virus. But some treatments can help make cold sores less painful and not last as long.

To ease pain, try holding a cold compress (a clean, cold, wet cloth) to your mouth. To make meals more comfortable, choose cool foods and drinks.

Medicines like acetaminophen or ibuprofen may also help. Do not take aspirin because it's linked to a rare but serious illness called Reye syndrome. Your doctor may recommend other medicine to help cold sores feel better and go away.

Someone with a cold sore should avoid touching it and be careful not to touch their eyes. If HSV-1 gets into the eyes, it can be very serious.

When Should I Call the Doctor?

Call your doctor if:

• You get cold sores often.
• You get a sore and have a weak immune system from another health condition (this could let the HSV infection spread and cause problems in other parts of the body).
• A sore doesn't start healing in 7–10 days.
• A sore is near your eyes or you have eye pain or redness.
• You have signs of a bacterial infection, like fever, pus, or redness that spreads.
• You have other symptoms, like a headache or confusion.

Can Cold Sores Be Prevented?

The HSV-1 virus is very contagious. To help prevent it from spreading, anyone with a cold sore should:

• Keep their drinking glasses, eating utensils, washcloths, and towels away from those used by others. Wash these items well after use.
• Not kiss other people until the sores heal.
• Wash their hands well and often, especially after touching a cold sore.