Polyarthritis as the initial symptom of secondary syphilis: case report and review.

The differential diagnosis of the patient with acute polyarthritis is lengthy. We present the case of a young man with acute inflammation of the knees and ankles in whom a diagnosis of acute rheumatic fever was initially considered. The clinical course and laboratory findings suggested that secondary syphilis was also a likely etiology of his problem. We believe that in some patients with acute polyarthritis, secondary syphilis must be seriously considered as part of the differential diagnosis.