Increased incidence of Trichophyton tonsurans tinea capitis in Ontario, Canada between 1985 and 1996.

In Canada, since the 1990s, Trichophyton tonsurans has emerged as the main cause of tinea capitis. Prior to this the more common agents were T. verrucosum, Microsporum canis and M. audouinii. Over the past few years the incidence of T. tonsurans has increased such that in 1985 and 1996 the cases of mycologically confirmed tinea capitis due to T. tonsurans were 9% and 76%, respectively. The epidemic of T. tonsurans has reduced the role of Wood's lamp in diagnosis of tinea capitis. The age distribution of tinea capitis due to T. tonsurans closely matches that of mycologically confirmed tinea capitis, being most common in children under 14 years of age. There is no significant sex difference in children who develop T. tonsurans tinea capitis; however, subjects are significantly more likely to live in urban than rural areas. This should provide guidance regarding where to concentrate health resources and deliver patient/parent education to combat this epidemic of tinea capitis.