What is complex regional pain syndrome (CRPS)?

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy syndrome (RSDS), is a chronic pain condition in which high levels of nerve impulses are sent to an affected site. Experts believe that CRPS occurs as a result of dysfunction in the central or peripheral nervous systems.

CRPS is most common in people aged 20 to 35. The syndrome also can occur in children; it affects women more often than men. CRPS may be heightened by emotional stress. There is no cure for CRPS.

What causes complex regional pain syndrome (CRPS)?

CRPS most likely does not have a single cause, but rather results from multiple causes that produce similar symptoms. Some theories suggest that pain receptors in the affected part of the body become responsive to catecholamines, a group of nervous system messengers. In cases of injury-related CRPS, the syndrome may be caused by a triggering of the immune response. Such a triggering may lead to the inflammatory symptoms of redness, warmth, and swelling in the affected area. For this reason, it is believed that CRPS may represent a disruption of the healing process.

What are the symptoms of CRPS?

The symptoms of CRPS vary in their severity and length. One symptom of CRPS is continuous, intense pain that gets worse rather than better over time. If CRPS occurs after an injury, it may seem out of proportion to the severity of the injury. Even in cases involving an injury only to a finger or toe, pain can spread to include the entire arm or leg. In some cases, pain can even travel to the opposite extremity. Other symptoms of CRPS include:

  • "Burning" pain
  • Swelling and stiffness in affected joints
  • Motor disability, with decreased ability to move the affected body part
  • An increased sensitivity to pain such that a very light touch to the skin can produce severe pain
  • Changes in nail and hair growth patterns. There may be rapid hair growth or no hair growth

CRPS also involves changes in skin temperature: skin on one extremity can feel warmer or cooler compared to the opposite extremity. Skin color changes also are apparent as the skin is often blotchy, pale, purple, or red. The texture of skin also can change, becoming shiny and thin. People with CRPS may have skin that sometimes is excessively sweaty.

Last reviewed by a Cleveland Clinic medical professional on 03/14/2016.


  • Binder A, Baron R. Complex regional pain syndromes. In: Koltzenburg M, McMahon SB, Tracey I et al. Wall & Melzack's Textbook of Pain. 6th ed. Elsevier Health Sciences; 2013: chap 67.
  • Goebel A. Complex regional pain syndrome in adults. Rheumatology (Oxford). 2011 Oct;50(10):1739-50. Epub 2011 Jun 28.
  • National Institute of Neurological Disorders and Stroke. Complex regional pain syndrome fact sheet Accessed 3/14/2016.
  • American Academy of Orthopaedic Surgeons. Complex regional pain syndrome (reflex sympathetic dystrophy) Accessed 3/14/2016.

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