Clinical and mycological analysis of twenty-one cases of tinea incognita in the Aegean region of Turkey: a retrospective study.

Tinea incognita is a dermatophyte infection with atypical clinical features modified by the improper use of corticosteroids or calcineurin inhibitors. The aim of this study was to analyze clinical and microbiological features of patients with tinea incognita. A total of 6326 patients referred to mycology laboratory between January 2008 and January 2011 for mycological examination with a diagnosis of tinea incognita were reviewed retrospectively. Twenty-one patients, 13 (61.9%) women and 8 (38.1%) men, mean age 42.2±36.8, were included in the study. Of them, lesions were localized in 15 (71.4%) patients and widespread in six (28.6%) patients. The mean duration of the disease was 9.5 (range 1-120) months. All patients had a history of treatment with steroids. Before admission, most of them had been misdiagnosed as eczema or psoriasis. Microscopic examination revealed hyphae and spores in most of the cases (n=17, 80.95%). Mycological cultures were positive in 19 (90.5%) patients. The most frequently isolated dermatophyte was Trichophyton rubrum (n=14, 66.7%). This case series revealed Trichophyton rubrum as the most frequent agent of tinea incognita. To the best of our knowledge, this is the largest case series from Turkey describing clinical features and mycological agents of tinea incognita.