Case report. Trichophyton mentagrophytes var. nodulare causing tinea pedis.

The identification of Trichophyton mentagrophytes var. nodulare is described, based on a strain recently isolated from tinea pedis. Different culture media and physiological tests were used in order to compare this strain with related strains. The main characteristics of T. mentagrophytes var. nodulare were its deep yellow-orange pigmentation, which was released from the mycelium, the flat growth of its colonies and the formation of nodular bodies. Supplementation of Sabouraud glucose agar with 3% NaCl reduced the aerial mycelium and stimulated the formation of conidia. Until now an identification of T. mentagrophytes var. nodulare based on DNA-patterns has not been published. Trichophyton mentagrophytes var. nodulare is supposed to be an anthropophilic dermatophyte causing ordinary tinea and onychomycosis. The low number of reports indicates that it is a very rare variety.