Tinea capitis in a dermatology center in the city of Fortaleza, Brazil: the role of Trichophyton tonsurans

Abstract

Over a 3-year period (March 1999 to March 2002), 944 patients with scalp lesions attended a dermatology reference center in the city of Fortaleza, Ceará, Brazil. Clinical specimens were examined at the Specialized Medical Mycology Center, Federal University of Ceará, Fortaleza-CE, Brazil, to detect patients with tinea capitis. Specimens were obtained from pus, scales, and hairs from suspected lesions of tinea capitis. Mycologic analyses were conducted by direct microscopy and by fungal culture on Sabouraud dextrose agar, with or without chloramphenicol and Mycosel agar. The culture tubes were incubated at 28 degrees C and examined daily for 1 month. Fungi were seen in 438 (46.4%) of the 944 clinical specimens. The percentage of positive direct microscopic examinations of the clinical specimens was 83.7%. Of those patients with tinea capitis, 157 (35.8%) were males and 281 (64.2%; P < 0.001) were females. The distribution of dermatophyte species in males, from 136 positive cultures, was Trichophyton tonsurans (54.41%), Microsporum canis (38.97%), T. rubrum (4.41%), T. mentagrophytes var. mentagrophytes (1.47%), and M. gypseum (0.74%). On the other hand, only three species, from 251 positive cultures, were present in females: T. tonsurans (80.08%), M. canis (17.53%), and T. rubrum (2.39%). There was a high proportion of positive results in children under 10 years of age (n = 309). No significant difference was detected in the seasonal distribution of tinea capitis. Our data show that T. tonsurans is the main etiologic agent of tinea capitis, and is more likely to be found in females and in the prepubertal population.