The causes of bruising on the body, which is not painful or itchy, include the following: 1, the body coagulation system dysfunction, due to the lack of coagulation factors in the coagulation system or hypersplenism, etc., resulting in excessive destruction of the number of platelets, which in turn causes too few platelets, etc., can lead to abnormal coagulation of the body, which in turn causes bruising on the body; 2, the body immune system dysfunction, causing increased vascular permeability, blood leakage The bruising is caused by the extravasation of blood; 3, bruising caused by purpura. You need to go to the hospital hematology department to do blood routine, coagulation and immune system examination to clarify, pay attention to do self-protection to avoid aggravation of bruising due to trauma, pay attention to the diet to strengthen nutrition, eat more iron-containing food.