Herpes is a viral infection that can infect the anal, genital or oral regions. It is estimated that 20% of the general population in the United States is affected. The majority of anorectal herpes infections are caused by HSV-2, with only about 10% being caused by HSV-1. Transmission is through autoinoculation or direct contact with an infected individual who is shedding the virus. After local inoculation, the virus travels along the nerves to the neuron’s nucleus.
A primary infection may cause an initial tingling sensation at the viral entry point, with subsequent eruption of the classic vesicles on a mucous membrane or skin surface. The vesicles are typically small and red, and may be clustered or scattered in the perianal skin, anal canal or perineum. The incubation period is between 4 and 21 days following anoreceptive intercourse.
Diagnosis is made on clinical examination, finding multinucleated giant cells with intranuclear inclusion bodies on Pap smear, a positive Tzank preparation or a positive culture. The use of antiviral medications has been shown to shorten the length of symptoms, but does not affect latency or recurrence rates. Suppressive antiviral therapy may be considered in patients who have more than five attacks per year.