IgA vasculitis is relatively common in children,especially in Asian countries. Abdominal manifestation could be severe, including bleeding, pancreatitis,appendicitis and intestinal intussusception. Delayed diagnosis could be fatal and cause severe complications.Nowadays no guidelines for those with severe abdominal manifestations in China.However, the most used treatment is steroid. For those severe forms are methylprednisolone pulse, IVIG, immunosuppressants and blood purification. Given the fact that different strategies lead to different endings which varies in cost, adverse effect and clinical outcomes in different medical centers, it is necessary to give birth to a useful and feasible strategy. This clinical trial is a muti-center, randomized,controlled prospective study.Patients with gastrointestinal disease will be recruited in three children's medical centres in Shanghai and will be randomized to two groups: MP group and IVIG group. Cost effect and clinical outcomes will be evaluated. Blood purification will be evaluated as a remedy when MP and IVIG fail to cure.