Complex Regional Pain Syndrome
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Complex Regional Pain Syndrome

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

En Español (Spanish Version)


Complex regional pain syndrome (CRPS) refers to a chronic condition affecting the nerves and blood vessels of one or more extremities. It is distinguished by extremely unpleasant burning sensations, swelling, sweating, color changes, and other distressing symptoms.

There are two types of CRPS:

  • CRPS 1—(also called reflex sympathetic dystrophy or RSD) No nerve damage exists with this type.
  • CRPS 2—(also called causalgia) This produces similar symptoms after a 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, which directs automatic body functions that a person cannot willfully control. Inflammation also may play a role in the disorder.

Risk Factors

A risk factor is something that increases your chances of getting a disease or condition. Minor or severe trauma increases the risk of CRPS:


If you experience any of these symptoms, do not assume it is due to CRPS. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your doctor.

The upper extremities, particularly the hands, are most commonly affected. Symptoms progress and may vary during the course of the condition. Pain may spread from one side of the body to another. Many doctors describe symptoms in terms of stages.

Within Hours or Days After Injury

Symptoms may include:

  • Deep aching or burning pain, typically more severe than expected from the injury
  • Sensitivity to touch or even a light breeze
  • Swelling in the arm or leg
  • Unusual sweating
  • Excessively warm or cool skin
  • Hair and nails changes

Symptoms may increase with stress and worsen over time.

Three and Six Months After Injury

Symptoms may include :

  • Burning pain moves to above and below the initial injury
  • Swelling in the arm or leg hardens
  • Muscle spasms or weakness develop
  • Extremity becomes cold
  • Hair growth slows
  • Nails become brittle or crack

Six Months or Later After Injury

Symptoms may include :

  • A pale, blue, and/or shiny appearance to the skin
  • Limited joint movement
  • Muscle loss


Your doctor will ask about your symptoms and medical history and perform a physical exam. 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:

  • X-ray —to check for signs of fracture and evidence of bone loss
  • Bone Scan —a special imaging test to check for early changes in bones
  • Thermogram—to measure heat radiating from the body, which may be diminished in CRPS extremity
  • Quantitative sudomotor axon reflex test (QSART)—a test which can quantify abnormality of the autonomic nervous system, such as sweating.


Treatment aims to relieve pain and improve function. Visit the doctor as soon as possible. Early therapy may lead to better outcomes.

Treatment options include:

  • Biofeedback
  • Acupuncture
  • Physical Therapy
    • Active and passive exercises help maintain function. Exercising in a warm pool may feel better than exercising on land.
  • Transcutaneous Nerve Stimulation (TENS)
    • A device worn on the skin surface creates a tingling sensation and may relieve pain in some cases.
  • Medication
    • Anti-anxiety medications, low-dose antidepressants, and drugs used to treat epilepsy may be effective.
    • Pain medications, such as narcotics, may be required to control severe pain.
    • Sometimes doctors will order other drugs to control symptoms.
  • Sympathetic Nerve Block
    • The injection of drugs that prevent the transmission of signals along sympathetic nerves may temporarily relieve pain in some cases.
  • Sympathectomy
    • If the nerve block is successful, a surgeon can permanently destroy sympathetic nerves. In some cases, surgery can worsen symptoms.
  • Psychological Support
    • Long-term pain often leads to depression or anxiety . Counseling is often required to help patients deal with chronic pain and loss of function.


Quick mobilization after surgery or injury can help minimize the risk of CRPS in the affected extremity.

In addition, a recent study builds on previous evidence that vitamin C may reduce the risk of CRPS after fracture. In the study, 416 mostly elderly women with fractured wrists were randomly given either a placebo or up to 1,500 mg of vitamin C daily for 50 days. Those patients who received vitamin C were significantly less likely to develop symptoms of CRPS compared to the placebo group. *


International Research Foundation for RSD/CRPS

The National Institute of Neurological Disorders and Stroke

Reflex Sympathetic Dystrophy Syndrome Association


BC Health Guide

Promoting Awareness of RSD and CRPS in Canada (PARC)


Ferri FF. Ferri's Clinical Advisor: Instant Diagnosis and Treatment. St. Louis, MO: Mosby Inc; 2005.

Goldman L. Cecil Textbook of Medicine. 22nd ed. WB Saunders Company; 2004.

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.

National Institute of Neurological Disorders and Stroke website. Available at: . Accessed August 2005.

Reflex Sympathetic Dystrophy Syndrome Association website. Available at: . Accessed August 2005.

Updated Prevention section on 8/10/2007 according to the following study, as cited by DynaMed's Systematic Literature Surveillance : 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.

Last reviewed January 2008 by Rimas Lukas, 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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