Genital herpes simplex virus is a sexually transmitted viral infection caused by herpes simplex virus type 2 (HSV-2) and type 1 (HSV-1). Most cases of recurrent genital herpes are caused by HSV-2, but an increasing proportion of anogenital herpetic infections have been attributed to HSV-1 (in particular, among young women and men who have sex with men [MSM]). This viral infection is spread from direct contact with active lesions (most common) or asymptomatic shedding (less common) of infected individuals. In women, vulvar, vaginal, and perineal lesions are most common. In men, lesions most commonly occur on the glans penis or penile shaft. Unilateral involvement of the upper buttock is another common presentation of HSV-2 in both women and men (sacral HSV).

Mucocutaneous HSV infection is characterized by initial outbreaks (primary infection), periods of latency (regional sensory ganglia), and recurrent flares localized to the area of the initial outbreak (recurrent infection). Stress, ultraviolet light, fever, tissue damage, and immunosuppression have all been associated with triggering recurrent flares.

The initial eruption usually develops within 5-7 days of inoculation and consists of painful vesicles, pustules, and/or erosions on an erythematous base that are scattered over the affected anatomic site. A prodrome of fever, malaise, and lymphadenopathy may precede or accompany the primary mucocutaneous eruption. In women, there can be severe local symptoms of vulvovaginal pain, dysuria, and vaginal discharge. If the anorectal area is primarily affected, there may be rectal pain and proctitis from intra-anal and rectal erosions.

Recurrent eruptions are usually less severe (fewer lesions, more localized, and less painful), resolve within 1 week, and lack a prodromal phase. Sacral HSV localizes to the upper buttock unilaterally, but bilateral involvement may sometimes be seen. Patients with genital HSV have an average of 4-7 recurrent outbreaks per year.

Low socioeconomic status, early age of first intercourse, a high number of sexual partners, and a history of prior sexually transmitted disease all confer an increased risk of developing genital HSV.

It is important to note that even when asymptomatic, a person sheds the virus and can, therefore, transmit the disease to another.

Immunocompromised Patient Considerations:
HSV infection in human immunodeficiency virus (HIV)-infected patients and other immunodeficiency states with T-cell defects is common and often presents with more severe and chronic disease. Recurrent outbreaks are more painful, more widespread, last longer, are poorly responsive to therapy, and have a higher risk of viremic dissemination. In addition, genital HSV infections in immunocompromised patients can have atypical presentations. Verrucous and exophytic nodules resembling condyloma acuminatum and verrucous carcinoma (Buschke-Lowenstein tumor) have been described. Chronic, nonhealing, painful ulcers occur, particularly in the perianal region. Infection with genital HSV confers an increased risk of acquiring and transmitting HIV. Others at risk for this include marrow and solid organ transplant patients and patients with lymphoma and leukemia.

Pregnant individuals with primary HSV infection are at increased risk for severe illness, ie, dissemination and hepatitis, particularly in the third trimester.