Q. My sister has a cold sore on her lip, and I'm afraid she may have passed the virus to my daughter. Is this possible?
A. Yes. Cold sores, also called "fever blisters," are caused by the relatively harmless herpes simplex virus and are usually transmitted by direct contact with oral secretions. They're typically located on the lips, but these small, red spots may also appear on the inside of the mouth, where they can cause painful ulcers.
Sometimes there will be clues that sores are about to break out -- most often tingling of the lips and in some cases drooling, a sore throat, and swollen glands -- a day or so before they show up. In other instances, there won't be any signs -- these viruses can live in the skin in a dormant state for months or even years, then erupt time and time again in response to a trigger, such as stress, a cold, or a sunburn.
If your daughter does develop a sore, in most cases it will heal and disappear within seven to ten days. In the meantime:
If cold sores become a nuisance, you should ask your pediatrician for a prescription topical antiviral medication, which can prevent a flare-up if applied at the first sign of an eruption.