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Complex Regional Pain Syndrome

(CRPS; Reflex Sympathetic Dystrophy [RSD]; Causalgia; Sympathetically Maintained Pain)

En Español (Spanish Version)

Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Complex regional pain syndrome (CRPS) refers to a chronic condition that affects the nerves and blood vessels of one or more limbs.

There are two types of CRPS:

  • CRPS 1, also called reflex sympathetic dystrophy or RSD, has no observable nerve damage.
  • CRPS 2, also called causalgia, produces similar symptoms after a verified nerve injury has occurred.

Complex Regional Pain Syndrome

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The cause of CRPS is not known. The condition likely results from several factors. It may involve overactivity of the sympathetic nervous system. This directs automatic body functions that a person cannot control. Inflammation may also play a role in the disorder.

Risk Factors

Factors that may increase your risk of CRPS include:


Symptoms usually appear after an injury. The most important symptom of CPRS is prolonged pain that may be constant or severe. There are different types and ranges of pain. Types of pain include burning, throbbing, aching, squeezing, or shooting.

Symptoms of CRPS change over time and may include:

  • Sensitivity to touch or even a light breeze
  • Swelling in the arm or leg
  • Unusual sweating patterns
  • Excessively warm or cool skin
  • Hair and nails changes which may become brittle and crack
  • Abnormal movement in the arm or leg, such as a tremor, jerking, or spasms
  • A pale, blue, and/or shiny look to the skin
  • Limited joint movement


Your doctor will ask about your symptoms and medical history. A physical exam will be done. To diagnose CRPS, the doctor uses four criteria:

  • An initial traumatic or painful event to a limb, or keeping the limb still for a period of time
  • Continuing pain in the limb that is out of proportion to any stimulus, such as pain with even light touch
  • Swelling, changes in skin blood flow, movement problems,or temperature changes only in the affected limb
  • No other cause for the symptoms

Tests may be ordered to rule out other conditions. Your doctor may refer you to a pain specialist for further evaluation and management. Tests may include the following:

  • Pictures may need to be taken of your internal body structures. This can be done with:
  • The electrical activity in your nerves and muscles may need to be tested. This can be done with:
  • You may need to have your body's heat measured. This can be done with a thermogram.
  • You may need to have your autonomic nervous system evaluated. This can be done with quantitative sudomotor axon reflex test (QSART).


Treatment aims to relieve pain and improve function. Early therapy may lead to better outcomes. In some cases, the condition goes away on its own; this is more common in children. Talk with your doctor about the best treatment plan for you. Options include:

Active and passive exercises help maintain function.

With a technique called mirror box therapy, you place your affected hand or foot in a box, which has a mirror on one side. While moving your limb inside of the box, you move your unaffected limb in front of the mirror. To your brain, it appears that you are moving your painful limb easily and without discomfort. Mirror box therapy may help to reduce pain and improve motor function in people who have CRPS due to stroke.

Long-term pain often leads to depression or anxiety. Counseling is often required to help patients deal with chronic pain and loss of function.

Your doctor may recommend the following medications:

  • Pain relievers
  • Antidepressants
  • Antiseizure medications
  • Bisphosphonates
  • Corticosteroids
  • Topical pain relievers that are applied to the skin
  • Nerve block injections

A surgical procedure called sympathectomy can permanently destroy sympathetic nerves. In some cases however, surgery may worsen symptoms.


Quick mobilization after surgery or injury can help minimize the risk of CRPS in the affected limb. Other steps that might be helpful include:

  • Early use of pain relievers after trauma
  • Use of sympathetic nerve block after trauma
  • Desensitization techniques, if needed
  • Use of vitamin C may reduce the risk of CRPS after a wrist fracture.

International Research Foundation for RSD/CRPS


Reflex Sympathetic Dystrophy Syndrome Association



Promoting Awareness of RSD and CRPS in Canada



Complex regional pain syndrome. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated June 24, 2013. Accessed June 27, 2013.

Harden RN, Bruehl SP. Diagnosis of complex regional pain syndrome: signs, symptoms, and new empirically derived diagnostic criteria. Clinical Journal of Pain. 2006;22:415-419.

Complex Regional Pain Syndrome Fact Sheet. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/reflex_sympathetic_dystrophy/detail_reflex_sympathetic_dystrophy.htm. Updated June 26, 2013. Accessed June 27, 2013.

8/10/2007 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Zollinger PE, Tuinebreijer WE, Breederveld RS, Kreis RW. Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study. J Bone Joint Surg Am. 2007;89:1424-1431.

11/9/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.phphttp://www.ebscohost.com/dynamed/what.php: Cacchio A, DeBlasis, E, Necozione S, di Orio F, Santilla V. Mirror therapy for chronic complex regional pain syndrome type 1 and stroke. N Engl J Med. 2009;361(6):634-636.

Last reviewed June 2013 by Rimas Lukas, MD; Brian Randall, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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