Complex regional pain syndrome (CRPS) usually develops after an injury, surgery, stroke or heart attack. The key symptom of CRPS is continuous, intense pain that is out of proportion to the severity of the injury. The pain gets worse over time. CRPS most often affects one of the arms, legs, hands, or feet, and the pain often spreads throughout the entire affected arm or leg.

Other signs and symptoms may include:
sensitivity to touch or cold
swelling of the painful area
changes in skin temperature, color, and/or texture
joint stiffness and swelling
muscle weakness and/or muscle spasms

Symptoms may change over time and vary from person to person. In some people, signs and symptoms of go away on their own. In others, symptoms can persist for months to years.