Mr. L, 62 years old, came to see me about a superficial “sore” on the shaft of his penis. The sore had first appeared about a month ago while Mr. L was on a three-week visit to relatives in Florida. He thought his penis might have gotten stuck in his zipper. A physician in Florida had already prescribed two courses of antibiotics. The initial medication was a first-generation cephalosporin. When that treatment was unsuccessful, the physician recommended a tetracycline derivative, presumably to cover possible community-acquired methicillin-resistant Staphylococcus aureus.
By the time Mr. L came to see me after returning from Florida, the sore was much improved. Only a shallow area of hyperpigmented skin measuring about 223 cm was visible on the penile shaft. The area was nontender, and there was no inguinal lymphadenopathy. The patient reported that he was monogamous with one same-sex partner and denied any high-risk sexual behavior.
WEIGHING THE DIFFERENTIALS
1 The list of differential diagnoses for genital ulceration in a male patient includes Behçet syndrome,
herpes simplex virus, squamous cell cancer, fixed drug eruption, chancroid, lymphogranuloma venereum,
and syphilis.
Behçet syndrome is typically associated with recurrent oral and genital ulcers, but our patient had only one lesion and no history of previous problems. Eye and skin lesions that may also be seen in patients with Behçet syndrome were absent. Painful vesicles that develop into shallow ulcerated areas may signal herpes simplex virus infection; recurrence of herpes lesions is common, although recurrence was not an issue in our patient. A persistent moist red plaque on the glans, shaft, or foreskin of the penis is the characteristic lesion of erythroplasia of Queyrat, a form of squamous cell carcinoma. Fixed drug eruption can appear as a dark red lesion that may be associated with burning and itching. Resolution occurs after withdrawal of the causative drug.
Three of the differential diagnoses in this patient were sexually transmitted infections (STIs)—chancroid, lymphogranuloma venereum, and syphilis. Chancroid is characterized by painful sores with a grayish base associated with inguinal lymphadenopathy. Lymphogranuloma venereum presents with a superficial painless erosion that generally heals on its own; the causative organism is Chlamydia trachomatis.
LABORATORY WORKUP
2 Because Mr. L had reported catching his penis in his zipper, the original treating physician had focused on infection. Since the lesion failed to respond to two courses of antibiotics, I turned my attention to the possibility of syphilis.
Laboratory studies included a VDRL test and serology for HIV. The VDRL came back highly positive at 1:256; the HIV test was negative. A positive fluorescent treponemal antibody absorption (FTA-ABS) test confirmed the VDRL results. Mr. L had primary syphilis.
DISCUSSION
3 Syphilis is an STI caused by the spirochete Treponema pallidum. The primary lesion, or chancre, occurs most often on the genitalia two to four weeks after exposure. The incubation period can be anywhere from 10 to 90 days after contact with an infected lesion. It is typically a painless ulcer that heals without scarring in two to six weeks. Syphilis is highly contagious.
Primary syphilis is diagnosed based on clinical presentation of a painless ulcer and confirmed by either darkfield microscopy or serology. Darkfield microscopy is specific for diagnosis but lacks sensitivity. The procedure requires expertise in performing, preparing, and viewing the sample with a microscope. Nontreponemal tests, such as the VDRL and rapid plasma reagin, become positive one to three weeks after the chancre appears. Lack of specificity requires confirmation with treponemal antigen tests, such as the FTA-ABS.
Secondary syphilis is characterized by a rash. The rash, which often involves the palms and soles, does not usually itch. Other signs and symptoms associated with secondary syphilis include fever, swollen lymph glands, sore throat, patchy hair loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve without treatment, but lack of treatment allows the infection to progress to the latent stage.
The latent or hidden stage of syphilis begins after reso-lution of the primary and secondary stages. The latent stage is asymptomatic and may last for years. Late-stage or tertiary syphilis develops in about 15% of individuals who have not been treated at an earlier stage. In the late tertiary stage, multiple organ systems may be involved. Neurologic problems include dementia, poor muscle coordination, numbness, and paralysis. Patients may also experience cardiovascular problems, such as damage to the aortic valve and aortic aneurysms.
The number of primary and secondary syphilis infections in the United States peaked in 1990 at 50,578 cases (20.3/100,000 population). By 1998 the number of primary syphilis cases had declined by 86% to 6,993 (2.6/100,000). Since 2001 the number of syphilis cases has steadily increased, with 11,181 infections reported in 2007; 64% of those cases were reported in men who have sex with men.
FOLLOW-UP
4 Mr. L was treated with 2.4 million units of benzathine penicillin IM. His partner underwent both HIV and VDRL testing and was also treated with IM penicillin. Mr. L will be followed with repeat serology six and 12 months after treatment. In Mr. L's case, I knew the results of a colleague's earlier treatment trials. The last physician to see the patient always has the advantage when making a diagnosis.
Dr. Schlam is assistant director of the Mountainside Family Residency Program in Verona, N.J.
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