Diagnosis: Tinea incognito
Description: Psoriasiform rash
Morphology: Plaque
Site: Foot,dorsum
Sex: F
Age: 47
Type: Clinical
Submitted By: Nameer Al-Sudany
Differential DiagnosisHistory:
Tinea circinata is a superficial skin infection with dermatophytes. It classically presents as a red patch or plaque with an active border and clear center. However, improper use of topical steroids based on mistaken diagnosis may alter the clinical picture into an odd or atypical presentation which usually lacks the active border and clear center pattern i.e. tinea incognito (steroid-modified tinea). The presented patient has been treated wrongly with potent topical corticosteroid after being diagnosed as foot eczema. Later she presented with red scaly pruritic plaques on the dorsum of the foot (Psoriasiform or eczematous-like rash). KOH mount preparation of lesional scales yielded positive results of tinea infection (hyphae and spores). She responded well to systemic antifungal therapy.