A Chinese-Japanese boy with black dot ringworm due to Trichophyton violaceum.

A 4-year and 8-month-old Chinese-Japanese boy, who had been visiting Dalian, China frequently, developed multiple alopecia lesions 1 year previously. At his initial visit to our department, multiple patchy alopecia with black dots was observed in the parietal scalp area. Multiple erythematous macules were also seen on the face, nape and right dorsum of the hand. A diagnosis of tinea capitis and tinea corporis was obtained on the basis of potassium hydroxide (KOH) microscopic examination of hair and scales from the lesions. Colonies grown on Sabouraud cycloheximide-chloramphenicol agar culture were examined using Fungi-Tape and MycoPerm-blue, and numerous microconidia and a small number of macroconidia were observed. Trichophyton violaceum was identified as the causative organism on the basis of colony morphology, microscopic morphology and molecular biology technique. As T. violaceum infection is not often seen in Japan, we suspected that the patient was infected by T. violaceum during his stay in Dalian. Conidia formation is rarely observed with T. violaceum, and only five cases with T. violaceum macroconidia formation have been reported in Japan (including this case). We also report the method for visualizing conidia formation of T. violaceum using Fungi-tape and MycoPerm-blue.