A 66-year-old woman presented with painful abdominal skin necrosis where she had been injecting subcutaneous enoxaparin 1 week following elective knee arthroplasty (Figure). Her complete blood cell count and basic metabolic panel yielded unremarkable findings. Enoxaparin was discontinued, a direct thrombin inhibitor started. Heparin platelet factor 4 IgG antibody strongly positive (2.065 OD), a...