The patient’s leg is bruised, which is a manifestation of subcutaneous bruising, generally common causes are mainly the following: a. Patients who accidentally fall leg can cause local capillary rupture, causing skin bruising appears bruised, at this time can be applied by ice local external, promote capillary constriction, avoid bruising range progressive expansion. Patients need to pay attention to rest, oral bruising pills, most local bruises in three to five days can be self-absorption, will not cause serious complications. Second, patients suffering from idiopathic thrombocytopenic purpura can also have bruise-like changes on the legs. At this time, patients can have multiple bleeding from teeth, mouth, stool, urine, and mucous membranes due to the significant decrease of the patient’s platelet index. If necessary, patients need to perform bone marrow aspiration and blood tests to clarify the cause, and actively give antiplatelet and anticoagulation therapy, so as to reduce the symptoms of subcutaneous bruising as much as possible.