Herpes is highly infectious just before and during blistering and ulceration and for about a week thereafter. However, there can still be some shedding of the virus even when a person is free of symptoms. An outbreak of genital herpes usually occurs in several stages over seven to ten days. Firstly there is a mild tingling or itching sensation which lasts 12-24 hours. Small blisters then form and tend to join with one another.
New blisters can subsequently appear.
The blisters are usually irritating, painful and tender. After 24-28 hours the blisters break to form shallow ulcers which may become infected unless healing occurs rapidly. The glands in the groin may become slightly painful, enlarged and tender. Finally, the ulcers disappear leaving a patch of redness or peeling for a few days. Previous infection with either type of herpes appears to increase immunity against the other types of herpes.