A 51years old lady presented to the dermatology department for recurrent painful, pruritic and malodourous erosive plaques in the intertriginous folds and scalp since the age of twelve years. Prior treatments included multiple courses of topical antifungals and antibiotics. Six of her siblings and nephews suffered from similar lesions. Physical examination revealed symmetrical extensive erythematous, macerated plaques with erosions over the scalp, axillae, groin and inframammary folds (Figs. 1 & 2), sparing the oral mucosa.