[Analysis of 25 cases of microsporum canis infection encountered at a dermatology clinic in Kumamoto during a recent 3-year period]

Twenty-five cases of dermatophytoses caused by Microsporum canis were encountered during a 3-year period (January 2008-December 2010). Their diagnosis was based on detection of fungal elements by direct microscopy and identification of M. canis by fungal culture. There were 17 women and 8 men ; they ranged in age from 4 to 85 years (mean, 34.6). The affected site was the head (n=5), face (n=8), neck (n=5), arm (n=8), leg (n=5), and trunk (n=5) ; exposed sites were those most often affected. A lone eruption was seen in 13 and multiple eruptions in 12 patients. The disease type was tinea corporis in 21 patients, tinea capitis in 5, and a combination of tinea corporis and tinea capitis in one. The disease showed familial onset in 10 patients (5 pairs), including 2 sibling pairs, 2 mother-child pairs, and 1 grandmother-granddaughter pair. Twenty-four patients had a history of contact with animals, and animals kept at home may have served as the infection source (cats in 23 patients and a dog in one). Hairbrush culture of the pets was positive in 9 patients. The patients with a lone eruption were treated with topical antifungal agents, while those with multiple eruptions of tinea capitis and tinea corporis were treated with oral itraconazole or terbinafine hydrochloride for 2-14 weeks, combined with topical antifungal therapy. Although reports of dermatophytoses caused by M. canis have been decreasing, our experience indicates the necessity of considering possible transmission of this disease from pets such as cats.