Painful red leg nodules and syphilis: a consideration in patients with erythema nodosum-like illness.

An adolescent girl presented with the classical physical findings of painful red nodules on the legs; the lesions were suggestive of erythema nodosum. The usual underlying causes were explored and found to be absent. Because she was sexually active, the patient was also routinely screened for sexually transmitted diseases. A rapid plasma reagin test was performed and found to be strongly positive. The confirmatory fluorescent treponemal antibody test was also positive. A diagnosis of syphilis was made, and she was treated with benzathine penicillin G (2.4 X 10(6) units). This report is a reminder that when a patient is suspected of having erythema nodosum, the physician should check for syphilis as well as for tuberculosis, sarcoidosis, reaction to a drug, and streptococcal disease. Panniculitis can be an important clinical sign of secondary syphilis that should never be overlooked.