Bruising after an impact is caused by bleeding or seepage of blood from the capillaries under the skin during the impact, and the blood is absorbed into the subcutaneous tissue, resulting in local bruising. If a patient has frequent bruising after an impact, it is possible that the body has certain pathologies, such as thrombocytopenia or abnormal coagulation. Platelets are normal substances in the blood, and a decrease in platelets can lead to a long time of blood clotting, which means that the blood vessels bleed easily. If the patient has a coagulation disorder, it may cause the patient’s bleeding to fail to clot on its own, resulting in more bleeding, etc. If necessary, come to the hospital for a checkup, you can check the blood routine to know the number of platelets, and also the coagulation routine to know the PT and APTT values.