Sort out those cold sores

Cold sores, those painful blisters that appear around the lips when you get a cold or go on a sunny holiday, are caused by the same type of virus that leads to genital herpes. Cold sores are caused by the herpes simplex virus type one (HSV 1). It is the most common form of the virus and causes 60 per cent of cold sores on the face and lips. Herpes simplex type two (HSV 2) usually infects the skin and mucous membranes of the genital area - hence it's known as genital herpes.

About 80 per cent of adults have blood evidence of previous HSV1 infection, whereas only 25 per cent have had an HSV 2 infection, though this number is steadily rising because of the increase in sexually transmitted infections of all types.

Both of these types of HSV can infect any area of skin or mucous membrane on your body. Herpes can also be spread from one person to another, even when there are no active blisters.

What are cold sores?
Cold sores are painful clusters of tiny fluid-filled blisters that usually appear near the lips. They can very occasionally appear at other sites on the skin and also inside the mouth. By the age of five most people have had an HSV infection, which then lies dormant in nerve cells. In some people the virus reactivates and they suffer recurrent attacks. It is estimated that eight out of ten people have had a primary or first HSV infection, though a large number will not have noticed much wrong.

What are the symptoms?
When you have your first attack, usually in childhood, the virus infects the skin before travelling along the nerve pathways to the nerve roots where it becomes inactive. It takes between one and three weeks from initial infection to develop the illness.