Cohen Philip R, Erickson Christof, Calame Antoanella
Dermatology, San Diego Family Dermatology, San Diego, USA.
Dermatology, Compass Dermatopathology, Inc., San Diego, USA.
Cureus. 2020 Jan 1;12(1):e6531. doi: 10.7759/cureus.6531.
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.
马拉色菌（糠秕孢子菌）性毛囊炎通常表现为上背部、胸部、伸侧手臂和面部出现瘙痒性单形性丘疹和脓疱。寻常痤疮、细菌性毛囊炎、嗜酸性毛囊炎和系统性皮质类固醇激素所致痤疮在临床上可模仿真菌引起的痤疮样病症。“隐匿型”这一名称用于描述当特征性表现被外用皮质类固醇激素治疗掩盖时的癣或疥疮。一名患有马拉色菌性毛囊炎的男性使用皮质类固醇乳膏后改变了皮肤损害的形态。他的皮肤表现——局限性炎症后色素沉着区域伴有扁平或完全消退的毛囊丘疹——增加了部分治疗的毛囊湿疹或毛囊接触性皮炎的可能性。皮肤损害活检的特征性表现确立了马拉色菌性毛囊炎的诊断；使用外用抗真菌洗发水和乳膏治疗后病情完全缓解。与隐匿型癣和隐匿型疥疮类似，由马拉色菌酵母引起的、其皮肤形态已被外用皮质类固醇激素治疗掩盖的毛囊炎应称为隐匿型马拉色菌（糠秕孢子菌）性毛囊炎。
