A patient had cold, cyanotic fingertips with small ulcerations. Laboratory testing showed leukocytosis, eosinophilia, and elevated D-dimer level; results of tests for antinuclear antibodies, antiphospholipid antibodies, antineutrophil cytoplasmic antibodies against proteinase 3 and myeloperoxidase, and HIV were negative. What is the diagnosis and what would you do next?