A case of monorecidive syphilitic chancre.

A 24-year-old man who had been in contact with a woman who had infectious syphilis developed a painless sore on his penis. His general practitioner prescribed tetracycline (250 mg four times a day for seven days). After approximately one month he developed another painless sore at the same site as the previous one. The diagnosis of syphilis was confirmed by dark-field microscopy and serologic tests. Reinfection was thought to be unlikely because he denied having sexual intercourse after the first visit to his general practitioner. Thus, the new lesion was thought to be a case of monorecidive syphilitic chancre.