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Cold Sores

What Is a Cold Sore?

Cold sores are small blisters that are reddish and a little painful. They're usually on the outer edge of the lip or inside the mouth.

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


What Causes Cold Sores?

Cold sores are caused by a virus called herpes (say: HUR-peez). Herpes is one of the most common viral infections in the world. The medical name for the virus that causes cold sores is herpes simplex.




How Can I Keep From Getting Cold Sores?

HSV-1 isn't a big deal. But it's a good idea to try to keep cold sores as far away as possible. If someone you know has a cold sore:

  • Don't kiss him or her.
  • Don't drink out of the same glass or use the same knife, fork, or spoon.
  • Don't share towels, washcloths, or napkins.



What Can I Do if I Have a Cold Sore?

For most kids, the sores go away on their own without any special treatment from a doctor. If you get a cold sore, try holding some ice wrapped in cloth or a cool washcloth on the sore. It also might help to eat a popsicle.



Reviewed by: Larissa Hirsch, MD
Date reviewed: February 2019