Tinea incognita is a dermatophyte infection of the skin whose clinical presentation has been modified by the misuse of steroids or, as has been described recently, calcineurin inhibitors. We report a case of pustular psoriasis treated with an antipsoriatic cream, composed of topical steroids and a vitamin D3 derivative, which gave rise to a tinea incognita. Our case underlines that clinical features of fungal infection can be modified by the increasing use of self-prescribed topical therapies, usually applied to treat incorrectly 'self-diagnosed' diseases. Moreover, we suggest that a mycological examination should be performed in every atypical presentation of skin lesion, and to rule out tinea pedis, in any disease of the feet that requires topical application of steroids.
Keywords: Calcipotriol; Self-administered therapy; Tinea incognita; Topical steroid.