Widespread Purpura as a Presenting Manifestation of Antiphospholipid Syndrome
A 46-year-old white woman with a history of Graves disease presented with pruritic and painful large purpuric patches, including some with central necrosis and eschars (Fig. A). The purpuric lesions initially appeared on her left arm and then rapidly progressed to involve her right arm, back, abdomen, chest, and face, affecting greater than 30% of her total body surface area, clinically resembling purpura fulminans. The patient denied a history of miscarriage. There was no family history of autoimmune disease. She had a mild fever of 100.2°F. Otherwise, her vital signs were stable, and the remainder of her physical examination was unremarkable. Initial laboratory studies revealed a normocytic anemia with hemoglobin 10.7 g/L (reference, 14–18 g/L), elevated D-dimer 545 mg/dL (reference, <0.5 mg/dL), elevated C-reactive protein 27 mg/dL (reference, < 3 mg/dL), and elevated erythrocyte sedimentation rate 90 mm/h (reference, <20 mm/h). A complete metabolic panel, coagulation profile, peripheral blood smear, blood cultures, and urinalysis were within normal limits. A skin biopsy (Fig. B) revealed intravascular thrombosis (Fig. C and D; arrowheads) with epidermal (Fig. C) and follicular epithelial necrosis. Additional laboratory studies revealed positive antinuclear antibodies 1:320 (reference, negative) and positive anticardiolipin immunoglobulin M (IgM) antibodies 16 U/mL (reference, <12 U/mL) and anti–β2-glycoprotein I IgM antibodies 137 U (reference, <15 U). The patient was diagnosed as having probable APS based on Sydney criteria. She was administered an intravenous heparin drip and oral prednisone. Over the next several days, she showed clinical improvement and was discharged to home on a slow prednisone taper and oral anticoagulation with warfarin. We followed her as an outpatient where the diagnosis of APS was confirmed with repeat positive anti–β2-glycoprotein I IgM antibodies of 97 U (reference, <15 U). Widespread purpura, including a purpura fulminans–like presentation, should be recognized as a potential cutaneous manifestation of APS.1–3 Additional cutaneous manifestations of APS include livedo reticularis, acrocyanosis, digital necrosis, and ulcers.