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

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.

Multiple lichen planus-like keratoses: Lichenoid drug eruption simulant and under-recognised cause of pruritic eruptions in the elderly.

We present six cases of multiple eruptive lichen planus-like keratoses (LPLK), occurring in older individuals predominately confined to previously solar exposed areas. Diagnosis was often confounded by the frequent histological reporting of 'lichenoid drug reaction' (LDR), despite many of the patients being unmedicated. We review the literature regarding eruptive LPLK and reflect on their etiology, clinical aspects, management and importantly their clinicopathological differentiation from LDR.

Is seborrhoeic dermatitis associated with a diffuse, low-grade folliculitis and progressive cicatricial alopecia?

An association between adult scalp seborrhoeic dermatitis and cicatricial hair loss has not previously been convincingly established. This study seeks to demonstrate a unique relationship between a clinically identifiable chronic scalp dermatitis-folliculitis with the characteristic histological features of low-grade inflammatory fibrosing alopecia, resulting in a distinctive progressive cicatricial alopecia which we believe is prevalent and hitherto unrecognised, and befits the description of seborrhoeic folliculitis. The clinical, epidemiological and histopathological features of seborrhoeic folliculitis are demonstrated to establish its unique status among the disorders of adult diffuse cicatricial alopecia.