Herpes simples virus (HSV, or herpesvirus) is a virus that causes infection of skin and mucous membrane and rarely infects other parts of the body. However, in the immunosuppressed patient, HSV may cause pneumonia and other more severe infections. When the infection occurs in the mouth it is commonly referred to as cold sores. An outbreak of HSV infection can be very painful. There are two distinct types of HSV: type 1 and type 2. It was believed that HSV-1 mostly caused oral herpes (herpes labialis), while HSV-2 generally caused genital herpes that typically affects the penis, vulva, and rectum. This is not completely true. Both type 1 and type 2 can cause herpes lesions on the lips or genitals. The first symptoms occur within 2-20 days after contact with an infected person.
Symptoms of the primary infection are usually more severe than those of recurrent infections. The primary infection can cause symptoms like those experienced in other viral infections, including lack of energy, headache, fever, and swollen lymph nodes in the neck. The first sign of infection is formation of fluid-filled blisters that may last up to two weeks. However, the pain in the area may last much longer. Once HSV enters the body it spreads to nearby mucosal areas through nerve cells. Once it infects the body the virus remains latent for the life of that individual. During the period of latency there are no symptoms. At times the infected person may shed the virus, even in the absence of visible symptoms, and infect others. Individuals infected with the virus can have recurrent infections; however, normally, recurrent infections are milder and shorter. However, cancer patients can have severe recurrences.
Typically, 50-80% of persons with oral herpes experience a prodrome (symptoms of oncoming disease) of pain, burning, itching, or tingling at the site where blisters will form. This prodrome stage may last anywhere from a few hours to one to two days. The herpes infection prodrome occurs in both the primary infection and recurrent infections.
Belinda M Rowland Ph.D., Malini Vashishtha Ph.D., The Gale Group Inc., Gale, Detroit,