Local bruising is easily caused after trauma and bumping, and the following conditions are considered: First, the poor elasticity and increased brittleness of blood vessels can easily lead to vascular damage after trauma, especially capillaries, which are commonly manifested by local exudate. Local bruising or hematoma formation with obvious tenderness will be found. Second, thrombocytopenia can lead to the occurrence of local bleeding events, which can easily form hematomas and bruises. Patients may show epistaxis or bleeding from brushing their teeth in general, mostly secondary to chronic liver disease, and easily if hypersplenism is present. Thirdly, abnormal coagulation mechanism can be seen in patients with prolonged chronic infections or patients with hemoembolism, which can easily affect the coagulation mechanism. Patients should usually pay attention to reasonable diet, systematic treatment and avoid trauma and other adverse stimuli.