BH28 A rare cause of scarring alopecia: shingles complicated by erosive pustular dermatosis of the scalp

Abstract

We report an unusual case of scarring alopecia in an 87-year-old man who presented with erosive pustular dermatosis of the scalp (EPDS) within the dermatome of a resolved herpes zoster ophthalmicus (HZO) infection 20 years prior. The patient was admitted with significant self-neglect. He presented with painless, thick scalp crusting, which developed over 3 years. Examination revealed thick, confluent, honey-coloured and green crusts on the left scalp. Removal of crusts exposed 1–2-cm erosions on a well-demarcated atrophic, scarred bald area on the left frontal, temporal and vertex of the scalp, clinically consistent with EPDS. Notably, the eruption respected a sharp midline demarcation, strictly adhering to the left ophthalmic (V1) dermatomal distribution. This area corresponded to a severe HZO episode in 2004 that resulted in localized scarring alopecia. The rest of his scalp hair was thick with normal underlying skin. Swabs yielded heavy Pseudomonas aeruginosa growth, consistent with colonization. A 4-mm punch biopsy demonstrated focal ulceration with a dense overlying neutrophilic exudate. The underlying dermis contained an infiltrate of lymphocytes, plasma cells and neutrophils. The adjacent epidermis showed reactive hyperkeratosis. Clinical features and histopathology were consistent with a diagnosis of EPDS with secondary Pseudomonas colonization, arising within an area of postherpetic scarring alopecia. This case exemplifies shingles as a rare cause of significant scarring alopecia (El Hayderi L, Nikkels-Tassoudji N, Nikkels AF. Hair loss after varicella zoster virus infection. Case Rep Dermatol 2013; 5: 43–7). This led to an area susceptible to sun damage due to the localized hair loss. Postherpetic scarring alopecia served as a site of injury, creating an ‘immunocompromised district’ in accordance with Wolf’s isotopic response (Wolf R, Brenner S, Ruocco V, Filioli FG. Isotopic response. Int J Dermatol 1995; 34: 341–8). This predisposed the patient to EPDS in a deceptive dermatomal distribution.