The most common type of purpura is the simple type, which mainly manifests as skin purpura. The purpura often occurs repeatedly in batches and is symmetrically distributed, and can be accompanied by skin edema and urticaria. The purpura is dark red at first and does not fade when pressed, it may fuse into a patch or slightly higher than the skin surface, showing a hemorrhagic rash or small urticaria, and in severe cases it may fuse into a large blood sore with hemorrhagic necrosis in the center. The purpura then gradually turns into purple, yellowish brown, yellowish, and gradually fades away after 7 to 14 days. In addition to skin purpura, there are a series of gastrointestinal symptoms and signs, such as nausea, vomiting, vomiting blood, diarrhea, mucus stool and blood in stool. Abdominal pain is the most common, often with paroxysmal colic. The abdominal signs are usually seen at the same time as the skin purpura, or occasionally before the purpura. Joint type (Schonlein type) In addition to skin purpura, there are also joint swelling, pain, pressure pain and functional impairment. It occurs in large joints such as knee, ankle, elbow, wrist, etc. It is wandering, recurrent, and heals after a few days without leaving joint deformity. The incidence of renal type can be as high as 12% to 40%. On the basis of skin purpura, hematuria, proteinuria and tubular urine appear, occasionally edema, hypertension and renal failure are seen. The renal damage mostly occurs 1 week after the appearance of purpura, but it can also be delayed and recovered within 3-4 weeks; in a few cases, it evolves into chronic nephritis or nephrotic syndrome due to repeated attacks. Mixed skin purpura combined with other clinical manifestations. A few patients may also develop symptoms and signs due to the involvement of the eye, brain and meningeal vessels.