Abstract: 【Abstract】 A 54-year-old man presented with a pruritic erythematous patch on the buttock that had been expanding over a periond of half a year. Physical examination disclosed a well-marginated erythematous patch measuring 7 cm × 12 cm; there were scattered scales on the surface, and the border was elevated. Microscopic examination of the scales with potassium hydroxide exhibited refractive hyaline hypha. Fungal culture showed velvety colony which developed on Sabouraud′s dextrose agar （SDA） plate. The fungus purified from potato dextrose agar （PDA） plate was found to have abundant rod-shaped microconidia and pear-shaped macroconidia by microscopy. The isolate was positive for urease reaction but negative for hair perforation test. The sequence of rDNA ITS region of the isolate was assessed and compared against Genbank database. A full consistence was observed between the ITS sequence of the fungal strain and the referrence sequence of ITS of T. rubrum. The isolate was identified as T. raubitschekii according to the above findings. The lesion completely healed after 2 weeks of treatment with oral terbinafine.

Key words: Trichophyton raubitschekii, Trichophyton rubrum, tinea cruris, Trichophyton raubitschekii, Trichophyton rubrum, Tinea corporis