Skin bruising and blackening when touched is considered to be related to coagulation disorders, thrombocytopenia, and vascular factors. 1. Coagulation dysfunction: coagulation dysfunction also belongs to the bleeding disorders, considering the lack of coagulation factors or abnormal function. The capillaries of patients with coagulation dysfunction bleed easily, and the touch of the outside world causes the capillaries to break, which can cause skin bruising. 2. Thrombocytopenia: after thrombocytopenia, the hemostatic function of the human body is impaired, and the capillaries are easy to rupture and bleed. 3. Vascular factors: Pathological factors, such as high blood lipids, the elderly due to the greater brittleness of blood vessels, prone to the above symptoms. Besides, the effect of drugs, vitamin deficiency, hypersplenism and so on may also cause the above symptoms. It is recommended to go to the hospital for examination to find the cause and treat for the primary disease.