Eight forms of herpes virus infect humans, causing a wide range of diseases. The two types of highly contagious herpes simplex viruses cause recurring sores or blisters. Type 1 causes cold sores around the lips and in the mouth, although sores can also spread to the genitals through oral sex. Type 2 herpes simplex causes genital herpes and spreads through sexual contact.
Illness
Upon initial infection with either type 1 or type 2 HSV, the patient might experience flu-like symptoms such as headache, fever and muscle aches within a few weeks of exposure to the virus. The symptoms precede the appearance of the typical lesions.
Cold Sores
The initial infection with type 1 HSV causes multiple painful, fluid-filled sores on the lips and on the gums or roof of the mouth. Lasting from around 10 to14 days, the first outbreak of oral herpes can be uncomfortable enough to interfere with normal eating and drinking. Some people experience only swollen gums in the first outbreak while some people have no symptoms at all. After the first outbreak, the virus lies latent or dormant in a collection of nerve cells near the spine. For reasons that are not entirely clear, at times HSV will activate and travel down the nerve fibers to the mouth and start another episode of blisters. The blisters are called cold sores because infection with a cold virus often reactivates the HSV. Usually after the first outbreak, subsequent outbreaks cause one cold sore.
Genital Lesions
Like the initial infection with type 1 HSV, the first infection with type 2 HSV or genital herpes often causes multiple, painful blisters on the genitals along with flu-like symptoms. Some people also experience a burning sensation during urination. In addition to the genitals, sores can form on the thighs or buttocks. Women might have sores inside the vagina or on the cervix while men might have sores on the penis or scrotum or in the urethra, the tube that carries urine and semen through the penis. According to the Merck Manual, the internal lesions are less painful. Like type 1 HSV, type 2 HSV also lies dormant until a trigger begins a new eruption of sores, usually less numerous and painful than in the original infection.
Prodrome
In cases of recurrent herpes lesions from HSV type 1 or type 2, skin in the affected area will tingle or itch for a few hours to a few days before a new outbreak of lesions appear. This phenomenon is called the prodrome.
Other
The Merck Manual outlines some other possible effects of HSV. HSV in the eyes causes sores on the cornea called herpes simplex keratitis. The sores cause pain and activate tear ducts; they increase sensitivity to light and blur vision. HSV infection of the brain, called herpes encephalitis, can cause confusion and seizures and can even be fatal.
