Acne necrotica (necrotizing lymphocytic folliculitis): An enigmatic and under‐recognised dermatosis

Abstract

Acne necrotica is a disorder of adults of obscure aetiology, featuring repeated cropping of inflammatory papulonodules which rapidly necrotise, leaving varying degrees of superficial scarring with pathological features in early lesions of a necrotising lymphocytic folliculitis. A perceived diminishing interest in this entity in recent years prompted a prospective study of patients presenting to a dermatology practice over a 3-year period to reassess the prevalence of this disorder in general dermatological patients, leading to the identification of 47 patients (35 female) with features of acne necrotica, with histopathology undertaken in atypical cases. We identified the importance of the recognition of primary lesions (1-2 mm umbilicated erythematous papules), often difficult to find in excoriated areas, as being paramount in the diagnosis both clinically and histologically in our study, which reveals a significantly more prevalent and clinically diverse disorder than featured in previous textbook and academic journal descriptions.

Story of a Scalp Studded with (Crateriform) Scars

“…As necrosis develops, histopathology reveals keratinocyte necrosis in the outer root sheath of the pilosebaceous unit, and neutrophilic infiltration in the adjacent epidermis and dermis. Established necrotized lesions show heavy non-specific perifollicular inflammation and remnant hair shafts [3,7,8], similar to the present case. Histopathology helped in ruling out the differential diagnoses such as gram-negative folliculitis, folliculitis decalvans, lupus miliaris disseminates faciei, pityriasis lichenoides et varioliformis acuta, and dermatitis artefacta.…”

Disorders of Hair

“…It is characterized by the presence of pruritic, painful, or tender follicular papulonodules that heal with scarring. There are five clinical forms of acne necrotica including classical (varioliform), miliaris, micropapular, cape distribution, and disseminate form (Pitney et al 2018). • Clinical feature: Lesions of classical and miliaris type are arranged on the face and neck area, and scalp and scalp margin area, respectively (Pitney et al 2018).…”

“…There are five clinical forms of acne necrotica including classical (varioliform), miliaris, micropapular, cape distribution, and disseminate form (Pitney et al 2018). • Clinical feature: Lesions of classical and miliaris type are arranged on the face and neck area, and scalp and scalp margin area, respectively (Pitney et al 2018). Primary lesions in the classical form are follicular, large, painful, umbilicated papules that undergo central necrosis with adherent hemorrhagic crusts and resolve with varioliform scar (Wu et al 2008).…”

“…Primary lesions in the classical form are follicular, large, painful, umbilicated papules that undergo central necrosis with adherent hemorrhagic crusts and resolve with varioliform scar (Wu et al 2008). Acne necrotica miliaris is presented with small, pruritic papulopustular lesions that heal with atrophic cribriform scars (Pitney et al 2018). • Pathological manifestation: In early lesions, there are a superficial lymphohistiocytic infiltrate, spongiosis, and necrosis in the outer root sheath spreading to the adjoining epidermis and dermis; later, necrosis of the upper pilosebaceous unit and adjacent epidermis and dermis is visible and at the end, established necrotized lesions are associated with heavy dermal inflammation (Pitney et al 2018).…”

“…Acne necrotica miliaris is presented with small, pruritic papulopustular lesions that heal with atrophic cribriform scars (Pitney et al 2018). • Pathological manifestation: In early lesions, there are a superficial lymphohistiocytic infiltrate, spongiosis, and necrosis in the outer root sheath spreading to the adjoining epidermis and dermis; later, necrosis of the upper pilosebaceous unit and adjacent epidermis and dermis is visible and at the end, established necrotized lesions are associated with heavy dermal inflammation (Pitney et al 2018). • Prognosis and treatment: Oral antibiotics, isotretinoin, and intralesional or topical corticosteroids are helpful in treatment (Wu et al 2008).…”