A 58-year-old man presented with a petechial and purpuric rash limited to the lower extremities. He reported that the rash had been present for months but worsened acutely over the last 3 days with new-onset dark urine, joint pain, and edema limiting his ability to walk. Physical examination showed areas of violaceous macules and papules on the legs and dorsal feet in a reticular distribution. Laboratory findings were remarkable for an elevated serum creatinine level of 2.75 mg/dL (reference range, 0.70–1.30 mg/dL), and serum immunofixation revealed the presence of markedly elevated IgG lambda monoclonal proteins. He was afebrile and his vital signs were stable. Dermatology, nephrology, and rheumatology services were consulted. What's your diagnosis? A. angioinvasive fungal infection B. antiphospholipid antibody syndrome C. calciphylaxis D. livedoid vasculopathy E. type I cryoglobulinemia