Telltale skin lesions of syphilis, gonorrhea, human papillomavirus infection, and Haemophilus ducreyi infection.
A 55-year-old man presented with a widespread eruption that had gradually arisen during the preceding month. Except for the slightly pruritic lesions, the patient had no other symptoms. He was taking no new medications; he denied new sexual contacts and behaviors that increase the risk of HIV infection.
A widespread and uniform distribution of 3- to 5-mm, moderately firm, intradermal papules was found on the trunk and extremities; only the palms, soles, and intertriginous areas were spared. The photograph shows the right anterior axillary area of the chest and arm. No oral involvement or alopecia was noted. Laboratory test results showed no evidence of dyslipidemia, diabetes, or autoimmune diseases.
Biopsy results ruled out the differential diagnoses of granuloma annulare, sarcoidosis, eruptive xanthoma, and lichen planus. Histologic examination demonstrated numerous plasma cells, which raised the suspicion of syphilis. Presented with these data, the patient admitted to an extramarital heterosexual contact several months earlier. The results of the reactive plasma reagin and fluorescent treponemal antibody absorption tests and microhemagglutination assay for antibody to Treponema pallidum confirmed the diagnosis of syphilis. Intramuscular benzathine penicillin G, 2.4 million units, was given.
The patient was seronegative for HIV infection. He will be retested in several months.
(Case and photograph courtesy of Joe Monroe, PA-C.)