Cold sores

Cold sores are very common and quite contagious, our expert tells you when a doctor's visit is in order

Q: My nine-year-old son has had two cold sores in as many months. How can we prevent them?

A: Cold sores are caused by the herpes type 1 virus and are very common. They often appear on the lips, but may also be on the gums and tongue, as well as around the nails, where they are called whitlows. They do not leave scars. The virus can remain dormant on the nerve in the area and can recur with illness, fever or sun exposure.

Most of the time, cold sores go away on their own in a few days. Many of my older patients say early application of creams shortens the duration of the blistering (I often prescribe a cream with acyclovir). However, in some children, the mouth ulcers are so painful that they cannot drink. Then treatment for the pain and dehydration may be needed. In newborns, children with widespread infection or those with low immunity, admission to hospital might be necessary. If your son gets widespread infections, or they seem to recur without any triggers, you should discuss this with his doctor.