As an autoimmune disease mediated by serum immunoglobulin A, allergic purpura is mainly manifested as systemic vasculitis, such as abdominal pain, skin purpura, proteinuria, joint swelling and pain, hematuria, and occasional intracranial hemorrhage. The disease is easy to relapse, and recurrent attacks and severe renal damage are also difficulties in clinical treatment, which have a certain impact on the actual prognosis of children. If the patient 's condition cannot be alleviated in a short time, it may lead to intussusception, skin infection and necrosis, which directly affects the patient 's life and health, thereby increasing the difficulty of clinical treatment. The traditional treatment of allergic severe purpura is mainly to remove the sensitizing factors, and to carry out symptomatic treatment and intervention, but there may be situations where the condition of the child cannot be effectively reversed. In recent years, blood purification technology has been widely used, and the clinical effect is exact. This article discusses the diagnosis of severe allergic purpura in children, and reviews the application progress of blood purification in children with severe allergic purpura, aiming to provide reference for the treatment of severe allergic purpura in children.