A 75-year-old African-American man with Type II diabetes, hypertension, and hyperlipidemia was admitted with a painful right leg secondary to bilateral iliac artery obstruction. Admission hemoglobin level was 14.4 g/dL, white blood count was 11.9 3 10 9 /L (neutrophils, 10.4 3 10 9 /L), and the platelet count was 366 3 10 9 /L. Unfractionated heparin 5,000 IU thrice daily by subcutaneous injection was given for 5 days. Aortobifemoral bypass surgery was performed with full-dose intravenous heparin followed by daily subcutaneous unfractionated heparin thromboprophylaxis. After an initial decline, the platelet count rose to 480 3 10 9 /L on postoperative Day 4 (Day 10 after start of preoperative course of heparin), at which time the patient developed a swollen right leg. Vascular duplex revealed a gastrocnemius vein clot of indeterminate age, which was not treated.This patient was found to have a gastrocnemius vein thrombosis on Day 4 after surgery. Controversy exists over whether to anticoagulate deep muscular vein thromboses. No large randomized trials have been done, and some smaller studies show similar resolution with or without anticoagulation [1,2]. Thus, the decision to continue subcutaneous (SC) prophylactic-dose heparin was reasonable.On postoperative Day 5, a right leg patchy retiform purpuric skin rash developed (Fig. 1A). Arterial duplex showed improved but still poor arterial flow to the right leg. Skin biopsy (right medial thigh) showed intravascular thrombus in a mid-dermal vessel and partial epidermal necrosis, without vasculitis (Fig. 1B,C). Laboratory investigations, including complete blood count, measurement of antithrombin, protein C, protein S, ANCA, cryoglobulins, homocysteine, viral hepatitis serology, complement, and antiphospholipid antibodies, were normal/ negative. The necrotic skin rash was considered secondary to "transient ischemia" during the preceding vascular surgery. The patient was discharged to a rehabilitation facility off heparin.The patient's right lower limb rash included multiple discrete lesions extending from the thigh to the ankle with blisters, SC hemorrhage, and necrosis in an angulated branched configuration described as "retiform purpura." These lesions have a broad differential, including vasculitis, hypercoagulable state, purpura fulminans, cholesterol embolism, thrombotic thrombocytopenic purpura, disseminated intravascular coagulation, warfarin-induced skin necrosis, heparin-induced skin necrosis, cryoglobulinemia, and calciphylaxis [3][4][5]. The biopsy finding of epidermal necrosis and intravascular thrombus without vasculitis, calcification, or inflammatory cell infiltrate, plus the negative hypercoagulability testing, lack of infection, renal failure, hemolysis, and absence of warfarin therapy, rules out most of these entities. Additionally, skin necrosis from low blood flow alone can be seen in livedo racemosa, but this entity is accompanied by a perilesional violaceous reticulated skin discoloration, which was not seen [3,4].Our patient had received SC inj...
