What Is a Cold Sore?

A cold sore is a small blister that forms on the outer edge of the lip. Some people call cold sores fever blisters.

Cold sores can appear one at a time or in little bunches. They're filled with fluid, then crust over and form a scab before they go away. They last about a week or two and usually don't need any treatment.

What Causes Cold Sores?

Cold sores are caused by a virus. The name of the virus is herpes (say: HUR-peez) simplex virus type 1 (or HSV-1, for short). Someone can get the virus by kissing someone with a cold sore or sharing personal items (like a towel, drinking glass, fork, or spoon) with them.

After a kid gets a cold sore, the HSV-1 virus stays in their body even after the cold sore goes away. And sometimes, the virus can make cold sores come back again.

How Can I Avoid Getting Cold Sores?

If you know someone who has a cold sore, try not to catch their germs. Don't kiss them or use their drinking glass, fork, spoon, or towels.

What Can I Do if I Have a Cold Sore?

Cold sores usually go away on their own, but sometimes doctors will treat them with medicine.

While you're waiting for the cold sore to go away:

• Wash your hands often so you don’t spread the virus to other people.
• Don't pick at the cold sore. Picking can spread the virus to other parts of your body. It can also make it take longer to heal.
• If you have pain, try placing some ice wrapped in cloth or a cool washcloth on the sore. It also might help to eat a popsicle. If the cold sore still feels uncomfortable, ask a parent if a pain medicine (like acetaminophen or ibuprofen) could help.

What Can I Do to Prevent Cold Sores From Coming Back?

Taking good care of yourself may help prevent cold sores from coming back. But sometimes they come back without a clear reason.

Here are some tips that may help prevent another cold sore:

• Try to get enough sleep and eat well so you don’t get sick.
• Try to manage stress by talking about your feelings with a trusted adult, getting lots of physical activity, and taking time to relax.
• Always wear sunscreen when you go outside, and don’t forget to put it on your face and lips.