Henoch-Schonlein Purpura (HSP) is the most common systemic vasculitis in childhood. The diagnostic criteria include palpable purpura with at least one other manifestation -- abdominal pain, IgA deposition, arthritis or arthralgia, or renal involvement. Immune complex deposits result in necrosis of the wall of small- and medium-sized arteries with infiltration of tissue by neutrophils and deposition of nuclear fragments, a process called leukocytoclastic vasculitis (LCV). It is often associated with infections, medications, or tumors. It may coexist with or mimic Crohn's disease. Periumbilical and epigastric pain worsens with meals, from bowel angina. Bleeding is usually occult or, less commonly, associated with melena. Intussusception, the most common surgical complication, is usually ileo-ileo or ileo-colic. Perforations, usually ileal, may occur spontaneously or be associated with intussusception. Ultrasound, recommended as the first diagnostic test, and CT scans may show intussusception and asymmetric bowel wall thickening mainly involving the jejunum and ileum. There are a range of endoscopic findings including gastritis, duodenitis, ulceration, and purpura, with the second portion of the duodenum characteristically being involved more than the bulb. Intestinal biopsies show IgA deposition and LCV in the submucosal vessels. Superficial biopsies may show inflammation, ulceration, edema, hemorrhage, and vascular congestion, presumably due to vasculitis-induced mucosal ischemia. The efficacy of corticosteroids in preventing severe complications or relapses is controversial. The majority of patients, however, improve spontaneously.