Also known as, a contusion, bruise or ecchymosis, a black and blue injury results from a blow to muscle and tissue that leaves the skin intact. Kids Health explains that when a black and blue injury occurs, blood capillaries burst and blood seeps out under the skin. The broken blood capillaries are what give the bruise its black and blue appearance. In most cases, a bruise will disappear on its own within two weeks. Caring for a black and blue injury will help to reduce the size of the bruise and relieve some of the pain associated with it.
Apply a cold compress to the black and blue injury for approximately 20 minutes immediately following the injury. After the initial 20 minutes, apply the cold compress every hour for the next 24 hours. Switch to a hot compress after the first 24 hours. Just like the cold compress, the hot compress requires application to the black and blue injury for approximately 20 minutes every hour. Continue applying the hot compress every hour for 48 hours. Elevate the bruised area for the first 24 hours following the injury. Keep the injury raised above the heart using a few pillows. Elevation will help to prevent blood from pooling in the injured area.