Bruises are due to bleeding (hemorrhage) into the tissue under the skin and can be caused by quite minor accidents. The symptoms of pain, swelling and tenderness, with some limitation of movement of the affected parts, usually subside fairly rapidly after one to two days. The bruise itself will remain longer and the gradual change of colour is due to the decomposition of the blood. Parents are often anxious that a bone may be broken but this is unlikely to have happened if the child is able to move the limb or bear his weight on it.
Apply a cold compress or ice pack to the bruises intermittently for the first 12 hours. Keep movement to a minimum for 24 hours.