Most of the bruises after trauma are due to local trauma, capillary bleeding, blood accumulation in the subcutaneous and soft tissues, and bruising on the surface. This bruising is usually a process of gradual yellowing of the bruise, followed by lightening, spreading and gradual absorption, which takes about 2-3 weeks. But there are some cases, there may be coagulation disorders, the bleeding not only not absorbed, but also have continued bleeding, such as thrombocytopenia, purpura with coagulation disorders, this condition will not be absorbed normally. In addition, there is more local bleeding, forming a hematoma, which may require surgical means to aspirate or drain the hematoma to absorb.