Cutaneous diphtheria masquerading as a sexually transmitted disease.

A 41 year-old, sexually promiscuous, married male, an agricultural laborer by occupation, presented to our sexually transmitted diseases (STD) clinic with multiple ulcers over the scrotum and genitalia of 20 days' duration. Bacterial culture from swabs taken from the genital ulcer, grew organisms morphologically and biochemically characteristic of Corynebacterium diphtheriae. He made a complete and uneventful recovery after two weeks of therapy with antidiphtheria serum and crystalline penicillin.