A bruise, also calle a contusion or ecchymosis, is an injury to biological tissue in which the capillaries are damaged, allowing blood to seep into the surrounding tissue. It is usually caused by blunt impact. Bruises often induce pain but are not normally dangerous. Sometimes bruises can be serious, leading to other more life threatening forms of hematoma, or can be associated with serious injuries, including fractures and internal bleeding. Minor bruises may be easily recognized, in people with light skin color, by their characteristic blue or purple appearance (idiomatically described as "black and blue") in the days following the injury.