After an injury such as a bruise, sprain or fracture of the arm or leg, complete healing and recovery occurs after a few weeks. In a small percentage of people, pain may persist at or around the injured site even though the skin or deeper tissues appear normal. This painful condition is called Complex Regional Pain Syndrome (CRPS). In some instances, the injury leading to CRPS may be so minor that patients sometimes cannot recall the injury or event that triggered CRPS.
CRPS usually affects one or more extremities, but may affect any part of the body. Pain is constant, sharp, burning, pricking or shooting in nature. There may be associated numbness and increased sensitivity to touch. Wearing socks over the affected foot can be extremely painful and intolerable. The affected arm or leg may even appear warm and flushed or cold and blue. Swelling and loss of hair can also occur. In chronic cases, x-ray may also demonstrate osteoporosis after one to two months from the onset of CRPS.