Herpes simplex virus infections are caused by two closely related viruses, identified as type 1 and type 2. They cause a wide variety of primary and recurrent mucocutaneous infections. Following a primary infection, the virus maintains a latent state, and recurrent disease is caused by reactivation of the latent viral infection.
Primary genital herpes is the most common cause of genital ulceration. The typical incubation period is 3 to 14 days after sexual exposure. The primary lesion begins as a small group of painful, pruritic vesicles, which break down to form ulcerating, pustular lesions in 2 to 4 days. By the time the patient sees a physician, the lesions are usually in the ulcerative phase. Painful, enlarged inguinal lymph nodes are common. New lesions will continue to form during the first week of the primary illness in about 75% of patients. About two-thirds of patients will have systemic symptoms including fever and headache. Fewer than 10 % of patients will develop aseptic meningitis or urinary retention. The duration of the illness may total 14 to 21 days.
In the immunocompromised patient, herpetic infections may be associated with progressive mucocutaneous ulcerations of the face, mouth, or anogenital regions. Lesions may coalesce, forming large, superficial ulcers that last for weeks or months.
Differential Diagnosis: Herpes simplex infection can be distinguished from cutaneous anthrax in the following manner.
Primary genital Herpes simplex
*Lesions begin as painful, pruritic grouped vesicles
* Vesicles break down to form an ulcer
* Lesions are located in the anogenital area
*Ulcer is painless
* Lesion is located on exposed parts of the body
*Ulcer and eschar are surrounded by characteristic non-pitting edema
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