Clinico-epidemiological study of tinea incognito with microbiological correlation.

BACKGROUND: Tinea incognito is a dermatophytic infection with a clinical presentation that is modified due to previous treatment with topical or systemic steroids, as well as topical immunomodulators. It tends to mimic other dermatological conditions.

AIMS: To evaluate the various clinical manifestations, sites, predisposing factors and causative agents of tinea incognito.

METHODS: A prospective observational study was done on one hundred clinically suspected cases of tinea incognito, with a history of topical or systemic steroid use for a period of at least six weeks. They were subject to direct microscopy and fungal culture, and re-evaluated at the end of the third and sixth week.

RESULTS: Eczema-like conditions were the most common clinical manifestation, followed by inflammatory, autoimmune and infective conditions. The face was the most commonly affected site. Direct microscopy was positive in 85% of cases, and fungal culture was positive in 63% of cases. Trichophyton rubrum was the most common species isolated. Pharmacists were responsible for 78% of tinea incognito cases, and betamethasone dipropionate was the most common drug used.

LIMITATIONS: As this was a hospital outpatient-based study, cases with severe systemic problems could have attended other departments. Cases involving the hair and nails were negligible.

CONCLUSIONS: Tinea incognito is a commonly encountered, yet poorly reported entity in the study population. An increased level of awareness and vigilance on the sale of steroid containing compounds will help control this dermatological condition.