what causes cold sores?

Answer 1

herpes simplex virus

Answer 2

Cold sores

Cold sores are a very common illness caused by the herpes simplex virus (HSV).

The disorder is characterised by groups of fluid-filled blisters which appear on red swollen areas of the skin or on the mucous membranes. The areas can be tender and painful. The blisters heal without scarring but have a tendency to recur.


There are two types of herpes simplex virus.


HSV-1, which is the most common type, usually causes cold sores (oral herpes). HSV-2 usually causes genital herpes. But both types can infect any area of the skin or mucous membranes.


Approximately 80 per cent of the adult population have antibodies against HSV-1 in their blood.


Around 25 per cent of the adult population have antibodies against HSV-2.

The virus can only be transmitted by close personal contact such as kissing. Most people will have come into contact with the virus between the ages of three and five but will not show any symptoms until after puberty.

HSV invades the cells of the epidermis, the outer layer of the skin, causing fluid-filled blisters to appear. The virus travels from the epidermis along the nerve paths to the roots of the nerves where it becomes inactive.

A weakening of the body's defences, due to a severe cold for example, can lead to a reactivation of the virus and a return of the blisters.

Answer 3

The herpes virus

Answer 4

A HERPES virus

Answer 5

herpes