A bruise is a discolored area under the skin that is caused by bleeding from small blood vessels in the underlying tissues. Over a few days, the bruise gradually changes color as the hemoglobin pigment in the leaked blood breaks down, and eventually the bruise fades completely.
Applying an ice pack can help to limit bleeding.
If a bruise does not disappear by itself within about 2 weeks or if bruising occurs unusually easily or for no obvious reason, a doctor should be consulted, because unusual bruising may be a sign of a blood clotting problem.