Herpes genitalis (or genital herpes) is a genital infection caused by the herpes simplex virus (HSV). A 1998 study indicated it was the most common sexually transmitted infection by the number of cases. Most individuals carrying herpes are unaware they have been infected and many will never suffer an outbreak, which involves blisters similar to cold sores. While there is no cure for herpes, over time symptoms are increasingly mild and outbreaks are decreasingly frequent.
HSV has been classified into two distinct categories, HSV-1 and HSV-2. Although genital herpes was previously caused primarily by HSV-2, genital HSV-1 infections are increasing and now cause up to 80% of infections.
When symptomatic, the typical manifestation of a primary HSV-1 or HSV-2 genital infection is clusters of genital sores consisting of inflamed papules and vesicles on the outer surface of the genitals, resembling cold sores. These usually appear 4–7 days after sexual exposure to HSV for the first time. Genital HSV-1 infection recurs at rate of about one sixth of that of genital HSV-2