The variability of syphilitic chancres.

Sixty-four patients who had darkfield microscopic evidence of primary syphilis underwent a standardized interview and physical examination. Two or more lesions were observed in 47% of patients, 7.8% of patients had non-indurated ulcers, and the borders of the ulcers of 7.8% were irregular and slightly undermined, suggesting lesions of chancroid. Only 27 patients (42.7%) had single, indurated chancres with regional lymphadenopathy. It is suggested that the "classic" chancre may be the "atypical" lesion.