The biopsy specimen revealed an unremarkable epidermis. There were small vessels within the superficial, middle, and deep dermis that demonstrated fibrinoid necrosis of the vessel walls, with an associated fibrin thrombi formation, as well as diffuse leukocytoclasia with marked extravasation of red blood cells, histologic findings that are most consistent with leukocytoclastic vasculitis.
The patient was admitted to the hospital, where she was treated with an oral prednisone taper, intravenous heparin, and supportive transfusions for worsening pancytopenia. Laboratory tests revealed the following values: white blood cell count, 3.9 × 103/µL (reference range [RR], 4.0-11.0 × 103/µL); hemoglobin, 6.3 g/dL (RR, 13.5-17.5 g/dL); and platelet count, 114 × 103/µL (RR, 150-400 × 103/µL). A bone marrow aspirate and biopsy specimen demonstrated hypercellular bone marrow, without evidence of transformation to acute leukemia. The patient did well, with normalization of her blood cell counts and marked improvement in her skin lesions with prednisone therapy.
Lower Extremity Purpura. Arch Dermatol. 2002;138(6):831-836. doi:10.1001/archderm.138.6.831