Purpura is caused by the leakage of blood around the blood vessel wall and its subcutaneous. The causes of purpura are complex and most of them can be classified as platelet-induced or vascular factor-induced purpura. Currently, the main cause of purpura caused by blood factor is the abnormal number of platelets, such as purpura caused by thrombocytopenia. In addition, some special cases of platelet increase may also cause purpura. In addition, the abnormal function of platelets may also cause purpura: first, the purpura caused by the blood vessel itself factors have the purpura caused by the increase of blood vessel pressure, easy to violent nausea, vomiting, coughing, may cause purpura; second, the abnormal structure of blood vessel wall can also cause purpura. When purpura occurs, you must go to the hospital for consultation and seek professional and formal guidance from your doctor to control the symptoms early and prevent further progress of purpura.