Idiopathic thrombocytopenic purpura (ITP) refers to thrombocytopenia caused by no obvious exogenous cause, but most of the time it is caused by increased platelet destruction caused by immune response, so it is also called autoimmune thrombocytopenia. It is a common type of hemorrhagic blood disease, characterized by shortened platelet lifespan, increased bone marrow megakaryocytes, IgG antibodies in serum or platelet surface in 80%-90% of cases, and no obvious enlargement of the spleen. According to the pathogenesis, inducing factors and course of disease, ITP is divided into acute and chronic types. 80% of children are acute type (AITP), with no gender difference. It is easy to get sick in spring and winter. Once the source of the disease is cleared, the disease will be cured in June-December. More than 95% of adult ITP are chronic type (CITP), with a male to female ratio of about 1:3. It is generally considered to be an autoimmune disease that is difficult to cure. The mortality rate of this disease is about 1%, and most deaths are caused by intracranial hemorrhage. The main clinical manifestations of ITP are bleeding in the skin and mucous membranes or internal organs.