An epidemic of infection with Trichophyton tonsurans revealed in a 20-year survey of fungal infections in Chicago.

Trichophyton tonsurans has long been recognized as an important, but hitherto uncommon, cause of tinea capitis in the United States. Today it is known to be more common, but infection of the glabrous skin by this organism is still not well appreciated. In an epidemiologic study during the two decades from 1961 to 1980, 1,292 isolates of thirteen species of dermatophytes were obtained from patients at Cook County Hospital, Chicago. During the last 3 years of study, T. tonsurans accounted for 207 cases (96%) of tinea capitis and ninety-seven cases (75%) of tinea corporis. Ninety-five percent of cases of tinea capitis caused by T. tonsurans occurred in children (59% girls, 41% boys). By contrast, 62% of cases of tinea corporis caused by that organism occurred in adults. Substantially more women than men were affected in a ratio of nearly six to one. The majority of the women were between 15 and 29 years of age; about half of all had lesions on the arm. Over the past 20 years, T. tonsurans has emerged as a major cause of both tinea capitis and tinea corporis in Chicago. The disproportionate number of cases of tinea corporis in women of childbearing age may be due to their more frequent contact with infected children.