Clinico-epidemiological study of tinea incognito with microbiological correlation

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.

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

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.

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.

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.

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.