Malassezia (Pityrosporum) Folliculitis Incognito: Malessezia-associated Folliculitis Masked by Topical Corticosteroid Therapy

Abstract

Malassezia (Pityrosporum) folliculitis usually appears as pruritic monomorphous papules and pustules on the upper back, chest, extensor arms and face. Acne vulgaris, bacterial folliculitis, eosinophilic folliculitis and systemic corticosteroid-induced acne can clinically mimic the fungal-caused acneiform condition. The designation incognito is used to describe tinea or scabies when the characteristic presentation is masqueraded by the application of topical corticosteroid treatment. Application of corticosteroid cream altered the morphology of the skin lesions in a man with Malassezia folliculitis. His cutaneous findings-localized areas of post-inflammatory hyperpigmentation with flattened or completely resolved follicular papules-raised the possibility of partially treated follicular eczema or follicular contact dermatitis. Pathognomonic findings from biopsies of the skin lesions established the diagnosis of Malassezia folliculitis; the condition completely resolved after treatment with topical antifungal shampoo and cream. Similar to tinea incognito and scabies incognito, folliculitis caused by Malassezia yeast in which the cutaneous morphology has been concealed by management with topical corticosteroids should be referred to as Malassezia (Pityrosporum) folliculitis incognito.