If bruises appear on the leg, the cause should be clearly defined. If the condition is caused by trauma, most of them are manifested as subcutaneous bleeding, and most of these patients will show obvious bruising, ecchymosis, or even obvious hematoma in the affected area. In addition, such patients also have obvious tenderness when pressing. If it is in the acute stage, try to apply cold compresses mainly, and in the later stage, we must pay attention to reducing weight bearing and activity, through which the bleeding can be reduced and also facilitate the absorption of petechiae. If bruises appear on the legs for no apparent reason, they are also often indicative of subcutaneous bleeding, which mostly originates from diseases of the blood system or clotting abnormalities. Commonly, hypersplenism, thrombocytopenia, or abnormalities in the coagulation system of the blood can also cause subcutaneous bleeding. For these patients, it is important to seek medical advice, exclude the cause, and do some tests, such as the five coagulation tests.