Frequency and aetiology of dermatophytosis in children age 12 and under in the state of Amazonas, Brazil.

Background: Few scientific studies have evaluated dermatophytosis among children in the state of Amazonas or in the greater northern region of Brazil.

Aims: The aim of this study was to research the frequency and aetiology of dermatophytosis in children age 12 and under, who were seen between March 1996 and November 2005 at the Mycology Laboratory of the National Institute of Amazonian Research.

Methods: For mycological diagnoses, epidermal scales and/or hairs were used. A portion of this material was treated with potassium hydroxide for direct examination, and another portion was cultivated in Mycobiotic Agar for the isolation of dermatophytes.

Results: Of the 590 samples analysed, 210 showed positive diagnoses by direct examination and cultivation. Tinea capitis (153 cases) was the most frequent type of dermatophytosis, and Trichophyton tonsurans (121 cases) was the most frequently isolated fungal agent. Tinea corporis was observed in 48 cases where the most frequently isolated fungal agent was also T. tonsurans (17 cases), and the corporal regions most affected were the face, arms and trunk. The laboratory confirmed tinea pedis in 6 cases, and the principal fungal agents isolated were Trichophyton rubrum (3) and Trichophyton mentagrophytes (3). The presence of tinea cruris was confirmed in 3 cases, and T. rubrum, T. tonsurans and Epidermophyton floccosum were isolated from these cases.

Conclusions: The children examined were primarily affected by tinea capitis, and the main fungal agent for this dermatophytosis was T. tonsurans.