Genital herpes is a sexually transmitted infection that can cause blisters and skin ulcers in the genital and anal area. It can be caused by either of two types of herpes simplex virus, HSV-1 or HSV-2. HSV-2 is the more common cause. HSV-1 more commonly causes sores on the face and mouth.
HSV spreads from person to person through kissing and skin-to-skin contact, as well as through vaginal, oral or anal intercourse. An infected person often transmits the virus when skin blisters or ulcers are visible, but the virus also can be spread when there are no symptoms or skin sores at all. Herpes virus can be transmitted by people who don't know they are infected.
In a pregnant woman with HSV infection (usually HSV-2), the virus can pass to the baby during delivery, causing infections of the newborn's skin, mouth, lungs or eyes. If the herpes virus spreads through the baby's bloodstream, it can cause serious infections of the brain and other vital organs.