The etiology of anorectal infections in homosexual men.

The infectious etiology of symptomatic anorectal disease was studied in 52 homosexual men who did not have gonococci on initial Gram stain of anorectal exudate. Herpes simplex virus (HSV) was isolated from the anal canal or rectum in 15 of the 52 (29 percent) men and characteristically caused severe anorectal pain and focal ulcerations visible on sigmoidoscopy. Despite negative initial Gram stains, seven men (14 percent) had anorectal gonococcal infection. Six (12 percent) had syphilis, including two with dark-field positive anal lesions. Four were infected with enteric pathogens, including Giardia lamblia, Entamoeba histolytica or Campylobacter fetus ssp. jejuni. Chlamydia trachomatis (LGV 2 strain) was isolated from one patient with severe granulomatous proctitis. One or more etiologic pathogens were identified in 28 (67 percent) of 42 men who had anorectal leukocytic exudate and in two of 10 who did not (p = 0.01). A review of the prominent features of different etiologic forms of anorectal infection in homosexuals is presented.