A Japanese case of tinea corporis caused by Arthroderma benhamiae

We report a case of tinea corporis in Japan caused by Arthroderma benhamiae. A 53-year-old female scientist, who had been working on dermatophytes in a laboratory, noticed pruritic erythema on the outer corner of her left lower eyelid. She used a steroid ointment for three days, but the lesion continued to expand. When she visited our clinic, the erythema was 15 mm in diameter and clearly demarcated with a slightly depressed center. A scale from the periphery of the erythema was positive with direct KOH examination, and T mentagrophytes was isolated from the lesion. The erythema was successfully treated with topical application of butenafine hydrochloride. The isolate was mated with a (+) strain of the Americano-European race of A. benhamiae. Using the most sensitive molecular typing method, restriction exzyme analysis of the non-transcribed spacer region of the ribosomal DNA, the restriction profile of the isolate was the same as that of strains used in her laboratory but different from those of any Japanese isolates associated with pet animals. The results suggest that the patient became infected during her experiment.