DP16 A rare case of recurrent cutaneous necrotizing eosinophilic vasculitis

Abstract

We present the case of a 42-year-old man with a 4-month history of small, exquisitely pruritic papules initially affecting the trunk and subsequently spreading to his wrists, proximal lower limbs and genitals. There were no associated systemic symptoms. His medical history included vitiligo and recurrent herpes simplex virus type 2 infection. There was no history of atopy. On examination, there were widespread excoriated, perifollicular pink papules with overlying scale and crust affecting the trunk, genital skin and proximal lower limbs bilaterally. Interdigital scaling and nail pitting were present. Initial management included topical emollients and mometasone furoate, with little response. Empirical therapy with topical permethrin and oral ivermectin was also administered to cover for possible scabies infestation. Due to persistent and worsening symptoms, punch biopsies were taken from the right buttock and right medial thigh. Histology (haematoxylin and eosin) demonstrated mild epidermal hyperorthokeratosis, mild spongiosis and a moderate superficial and deep perivascular and perieccrine eosinophil-rich chronic inflammatory cell infiltrate, extending to the superficial subcutis. Extravasation of red blood cells, endothelial swelling with focal fibrinoid necrosis and intravascular fibrin thrombi were present, without leucocytoclasis. Interstitial eosinophils were also noted. Periodic acid–Schiff staining was negative and no organisms were identified. These features were consistent with necrotizing eosinophilic vasculitis, supporting a diagnosis of recurrent cutaneous necrotizing eosinophilic vasculitis (RCNEV). RCNEV is a rare small-vessel vasculitis typically presenting with pruritic erythematous-to-purpuric papules or plaques, often associated with angio-oedema. Peripheral eosinophilia is common and immunoserological studies are typically unremarkable. This patient was commenced on high-dose corticosteroids with initial rapid clinical improvement, although relapse occurred during tapering. This case highlights RCNEV as an uncommon but important cause of treatment-refractory pruritic eruptions. Recognition of the distinctive histological pattern and clinicopathological correlation is essential to establish the diagnosis and guide timely systemic therapy.