What are they?
Cold sores, also called fever blisters, are quite common in childhood, affecting thousands of kids (and adults) each year. A virus called herpes simplex causes them. This name tends to strike fear in the hearts of those who hear it because they recognize this as the virus associated with the sexually transmitted disease genital herpes. However, these viruses, although similar in name, are distinct infections.
What are the symptoms?
Some children acquire the virus and have few, if any, symptoms. Others get the infection and develop many sores in and around the mouth. These blisters can be quite painful and are associated with a low-grade fever. The children have difficulty swallowing their saliva because of the pain it causes. They may have a poor appetite, and the glands around the neck may swell slightly and be mildly tender. Fortunately, this initial severe infection tends to be a one-time occurrence. Unfortunately, once infected, these children become carriers of the virus, which may last for a lifetime.
Some children never have another cold sore after the initial infection, while others develop recurrent sores, usually after episodes of stress such as fever, sunburn, or injury to the mouth. These sores usually recur in the same spot because, after the virus causes the cold sore, it travels back down the nerve to lie dormant deep inside the body. When it is reactivated in those times of stress, it travels along the same nerve right back to the same spot it infected previously.