BI47 The illusion of vasculitis: Evans syndrome presenting with palpable purpura

Abstract

Evans syndrome is a rare autoimmune condition defined by the coexistence of immune thrombocytopenia and autoimmune haemolytic anaemia. Cutaneous involvement is usually haemorrhagic in nature but can closely mimic small-vessel vasculitis, creating diagnostic difficulty. We describe an 83-year-old man who presented with painful, palpable purpura affecting both lower limbs, initially suspected to represent cutaneous vasculitis. His medical history was significant for chronic inflammatory demyelinating polyneuropathy, for which he had received long-term intravenous immunoglobulin (IVIg). IVIg had been discontinued several months prior to presentation. Initial blood tests revealed profound thrombocytopenia (platelet count 0.001 × 1012 cells L−1) alongside anaemia, prompting urgent referral to haematology. Blood film examination confirmed true thrombocytopenia, and further investigations supported a diagnosis of autoimmune haemolytic anaemia. A comprehensive vasculitic screen was negative, urinalysis showed no evidence of renal involvement, and cross-sectional imaging demonstrated no underlying malignancy. In the context of concurrent immune thrombocytopenia and autoimmune haemolytic anaemia, the diagnosis of Evans syndrome was made. At presentation, the patient had active mucosal bleeding. Given the extreme thrombocytopenia, skin biopsy was appropriately deferred because of the significant bleeding risk and the low likelihood of additional diagnostic value. Treatment was initiated with intra­venous corticosteroids, tranexamic acid and IVIg, followed by rituximab and eltrombopag. This resulted in a sustained improvement in platelet count and complete resolution of the cutaneous lesions. This case highlights Evans syndrome as an important mimic of cutaneous vasculitis. It underscores the importance of early full blood count assessment in patients presenting with vasculitic-appearing purpura, allowing timely haematology-led management.