Idiopathic thrombocytopenic purpura is currently called primary immune thrombocytopenia. The disease is serious because it is characterized by bleeding as the first manifestation, such as nose bleeding in some children, excessive menstrual blood in lesbians, and in most people, skin bleeding, many small red dots in both lower limbs, or even more blood blisters in the oral mucosa, which should be rushed to the hospital. However, bleeding in some people is not correlated with platelet count; the lower the platelets, the higher the risk of bleeding. However, it is now found clinically that some people have platelet bleeding that is not necessarily proportional to low platelets, such as someone with a platelet count of 20,000/mm^3, but can not bleed, or even look closely at the patient’s skin with only 1-2 scattered red dots, so bleeding is not obvious. Therefore, at present, domestic about platelet bleeding, can not be the only platelet count to measure the severity of the disease, the main thing is to look at the bleeding, if bleeding a lot is a very serious disease.