hematology and oncology
Dysproteinemias Causing Vascular Purpura
Immunoglobulin A–associated vasculitis
 Immunoglobulin A–Associated Vasculitis (IgAV) (Henoch-Schonlein purpura) is an IgA-mediated small-vessel vasculitis that occurs primarily in children. It involves the skin, joints, intestine, and kidneys. Palpable purpura develops mainly on the lower legs and buttocks. Because of its distribution, it can be confused with Erythema Nodosum , a reactive inflammatory panniculitis that can occur in patients with a variety of infectious, immunologic, neoplastic, and drug-induced disorders. 