Diseases Characterized by Genital, Anal, or Perianal Ulcers

In the United States, most young, sexually active patients who have genital, anal, or perianal ulcers have either genital herpes or syphilis. The frequency of each condition differs by geographic area and population; however, genital herpes is the most prevalent of these diseases. More than one etiologic agent (e.g., herpes and syphilis) can be present in a genital, anal, or perianal ulcer. Less common infectious causes of genital, anal, or perianal ulcers include chancroid and donovanosis. Genital herpes, syphilis, and chancroid have been associated with an increased risk for HIV acquisition and transmission. Genital, anal, or perianal lesions can also be associated with infectious as well as noninfectious conditions that are not sexually transmitted (e.g., yeast, trauma, carcinoma, aphthae, fixed drug eruption, and psoriasis).

A diagnosis based only on medical history and physical examination frequently is inaccurate. Therefore, all persons who have genital, anal, or perianal ulcers should be evaluated; in settings where chancroid is prevalent, a test for Haemophilus ducreyi also should be performed. Specific evaluation of genital, anal, or perianal ulcers includes 1) syphilis serology, darkfield examination, or PCR testing if available; 2) culture or PCR testing for genital herpes; and 3) serologic testing for type-specific HSV antibody.

No FDA-cleared PCR test to diagnose syphilis is available in the United States, but two FDA-cleared PCR tests are available for the diagnosis of HSV-1 and HSV-2 in genital specimens. Some clinical laboratories have developed their own syphilis and HSV PCR tests and have conducted Clinical Laboratory Improvement Amendment (CLIA) verification studies in genital specimens. Type-specific serology for HSV-2 might be helpful in identifying persons with genital herpes (see Genital Herpes, Type-Specific Serologic Tests). In addition, biopsy of ulcers can help identify the cause of ulcers that are unusual or that do not respond to initial therapy. HIV testing should be performed on all persons with genital, anal, or perianal ulcers not known to have HIV infection (see Diagnostic Considerations, sections on Syphilis, Chancroid, and Genital Herpes Simplex Virus).

Because early treatment decreases the possibility of transmission, public health standards require health-care providers to presumptively treat any patient with a suspected case of infectious syphilis at the initial visit, even before test results are available. Presumptive treatment of a patient with a suspected first episode of genital herpes also is recommended, because successful treatment depends on prompt initiation of therapy. The clinician should choose the presumptive treatment on the basis of clinical presentation (i.e., HSV lesions begin as vesicles and primary syphilis as a papule) and epidemiologic circumstances (e.g., high incidence of disease among populations and communities and travel history). For example, syphilis is so common in MSM that any man who has sex with men presenting with a genital ulcer should be presumptively treated for syphilis at the initial visit after syphilis and HSV tests are performed. After a complete diagnostic evaluation, at least 25% of patients who have genital ulcers have no laboratory-confirmed diagnosis (313).