Case of kerion celsi caused by Microsporum gypseum (Arthroderma gypseum ) in a child.

We report a case of kerion celsi caused by Microsporum gypseum and present some epidemiological statistics and a distribution of the mating types of M. gypseum . A 10-year-old healthy boy living in Narita, Chiba Prefecture, visited the Narita Red Cross Hospital in October 2004 with complaints of a scaly erythematous plaque and alopecia. Before the visit, he had been treated with steroid lotions and antibiotics without success. A direct examination of the diseased hair shaft using a potassium hydroxide (KOH) solution revealed the presence of fungal hyphae outside the hair shafts. The patient showed a positive reaction to the trichophytin test. The fungus isolated from the lesion was identified as M. gypseum on the basis of its morphological and physiological characteristics and the results of molecular biological analysis. The sequence of the gene coding for the internal transcribed spacer (ITS) 1 region of ribosomal RNA (ITS 1 rDNA) was homologous to that of Arthroderma gypseum (DDBJ accession no. AB193684). The isolate was confirmed to be A. gypseum (-) mating type on the basis of crossing experiments with (+) and (-) mating types of A. gypseum, A. incurvatum , and A. fluvum . The patient was successfully treated with 50 mg/day (1.6 mg/kg/day) of itraconazole for 4.5 months.