An abrasion is a superficial injury to the skin, usually caused by scratching, "grating", burning or brushing. This injury occurs when the skin scratches a hard surface and small blood vessels rupture in the outer layer of the skin. Abrasions are usually minor injuries that you can treat at home, but it is important to wash the affected area with soap and water, but not to rub the wound. Remove all dirt particles from the area and let tap water run over it for a few minutes. Dirty abrasion that is not well cleaned can cause scarring.