Man With Ulcer on His Penis

By NAVIN M. AMIN, MD-Series Editor, Primary Care Section


A 44-year-old homeless man complains of a “sore” on his penis. The ulcer developed from a macular lesion on the glans penis about 5 days earlier. The painless ulcer has not responded to a topical antibiotic ointment he received at another clinic. He denies any history of trauma, fever, rash, or joint problems. He had acute bronchitis a month ago and was given tetracycline(. He smokes a pack of cigarettes a day and drinks 2 or 3 beers daily, but he does not take illicit drugs. He is sexually active; his last contact was with a prostitute about 3 weeks earlier. This man is poorly nourished but not in distress. Pulse rate is 80 beats per minute and regular; respiration rate, 24 breaths per minute; blood pressure, 110/60 mm Hg. He is afebrile; hydration status is good. Dentition is poor. Small, shotty, rubbery, discrete inguinal glands are palpable. No periurethral discharge is noted. A well-demarcated circular ulcer with serous discharge is present on the glans penis. The margin is elevated, and the base is smooth and firm. The remainder of the examination is normal. You order a darkfield microscopic examination of the serous discharge. What does the slide suggest is wrong-and to what diagnosis does the clinical picture point?
A. Antibiotic (tetracycline)–induced ulcer
B. Herpetic lesion
C. Syphilitic chancre
D. Penile cancer
E. Lymphogranuloma venereumThe slide shows a typical spirochete, Treponema pallidum. In conjunction with this finding, the patient’s history of sexual contact with a prostitute; the painless, well-demarcated ulcer with a firm base; and the shotty, rubbery inguinal adenopathy strongly suggest primary syphilis, C. Hemoglobin level is 11.2 g/dL; white blood cell count, 7200/µL, with normal differential; platelet count, 200,000/µL. Urinalysis results are normal. HIV testing is negative. The VDRL test is positive. The fluorescent treponemal antibody absorption (FTA-ABS) test is also positive. He is given benzathine penicillin, 2.4 million units IM. Unfortunately, the patient is lost to follow-up. A CASE IN POINT Differential diagnosis. Genital ulceration is frequently encountered not only in sexually transmitted disease clinics but also in the primary care setting. The most common causes of painful ulcers are human herpesvirus 1 and human herpesvirus 2 infections; Haemophilus ducreyi infection, which causes chancroid; malignancy; drug-induced ulcer; and trauma. Painless ulcers are usually caused by T pallidum infection, granuloma inguinale, and lymphogranuloma venereum. Epidemiology. Coincident with the spread of AIDS in the 1980s and early 1990s, the incidence of syphilis increased. Nearly 150,000 new cases are diagnosed each year in the United States (16.8 cases per 100,000 population); the incidence is higher in cities such as Miami, Atlanta, New York, and Washington, DC. The incidence is 9 times higher among African Americans and Hispanics than among whites. Transmission. Infection is usually acquired by sexual contact, including orogenital and anorectal; by kissing; or by close body contact. Congenital syphilis can be transmitted from an infected mother to the infant. The incubation period varies from 1 to 13 weeks; 3 to 4 weeks is typical. Clinical features. The disease progresses through primary, secondary, latent, and tertiary stages (Table 1). In the primary stage, the classic lesion is a chancre that evolves and heals within 4 to 8 weeks in untreated patients. After infection, a red papule usually develops and quickly forms a painless, well-demarcated (“punched out”) ulcer that has an indurated base and exudes clear serous discharge (Table 2). Typically, the regional lymph nodes are enlarged, firm, rubbery, discrete, and nontender. Chancres can occur at different sites; the most common are the penis, anus, and rectum in men and the vulva, cervix, and perineum in women. Chancres may also occur on the lips or the oropharyngeal area (Figure). Diagnosis. The classic presentation of a primary syphilitic ulcer and the laboratory results establish the diagnosis. Darkfield examination of the serous fluid from the ulcer or aspirate from a regional lymph gland reveals a bright, motile, spiral organism that is 0.25 μm wide and 5 to 20 μm long and has 8 to 12 curves. There are 2 classes of serologic tests for syphilis:


  • Nonspecific tests. VDRL and rapid plasma reagin (RPR) are nonspecific tests that may be negative initially. These tests may not become positive until 3 to 4 weeks after exposure.
  • Specific treponemal tests. If the VDRL or RPR test is reactive, order a specific treponemal test, such as FTA-ABS, microhemagglutination assay to T pallidum (MHA-TP), or T pallidum hemagglutination assay (TPHA).

Treatment. Once the diagnosis of primary syphilis is established, the drug of choice is IM penicillin, 2.4 million units (1.2 million units in each buttock) once. Alternative regimens for patients who are allergic to penicillin are IV or IM ceftriaxone(, 1 g/d for 3 days; oral doxycycline(, 200 mg bid for 15 days; or oral tetracycline, 500 mg q6h for 15 days. Follow-up. Plan follow-up visits and serologic (VDRL quantitative) testing at 1, 3, 6, and 12 months. The patient also needs to be tested for HIV. Syphilis is a reportable disease. Sexual contacts must be traced (which is done by the public health department) and promptly treated.