Dermatophytosis caused by Trichophyton rubrum mimicking syphilid: a case report and review of literature.

A 56-year-old man who was under chemotherapy presented with a 2-week history of erythema on the left palm, soles, glans penis and the foreskin with no itching and pain. Initially syphilid was suspected. However, both toluidine red unheated serum test (TRUST) and treponema pallidum particle agglutination assay (TPPA) were negative. Microscopy showed hyphae in all sites and skin culture revealed Trichophyton rubrum infection, consistent with the diagnosis of tinea infection. He was cured with oral terbinafine for 2 weeks. We report here a case of tinea incognito caused by T. rubrum mimicking syphilid and review the literature.