by EBSCO Medical Review Board
(CRPS; Reflex Sympathetic Dystrophy [RSD]; Causalgia; Sympathetically Maintained Pain)


Complex regional pain syndrome (CRPS) is lasting pain in one limb that happens after an injury.

Type 1 happens after a soft tissue or bone injury. It is the most common type. Type 2 happens after a nerve injury.

Complex Regional Pain Syndrome
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CRPS may happen after:

How CRPS develops is not clear. One or more below may play a role:

  • Genes
  • How the immune system works
  • Mental health problems such as anxiety, anger, stress, or depression

Risk Factors

This problem is more common in women, especially those of European descent. It is also more common in adults.

Other things that may raise the risk of this problem are:

  • Migraine
  • Prior surgery that involved long-term tourniquet use
  • Certain genetic disorders


Symptoms mainly appear after an injury. The most common is long-term pain. It may be constant or severe. Pain is described as burning, throbbing, aching, squeezing, or shooting.

These may change over time and cause:

  • Sensitivity to touch or even a light breeze
  • Swelling in the arm or leg
  • Sweating patterns that are not normal
  • Very warm or cool skin
  • Hair and nails that become brittle and crack
  • Movements in the arm or leg such as a tremor, jerking, or spasms
  • A pale, blue, or shiny look to the skin
  • Poor joint movement


The doctor will ask about your symptoms and health history. A physical exam will be done. This may be enough to make the diagnosis.

Nerve tests may be done, such as:

Imaging tests usually are not needed unless there is a certain reason to have them.


The goal of treatment is to ease pain and improve function. Options are:

  • Physical and occupational therapy to help with muscle strength, flexibility, and daily activities
  • Medicine to help manage pain, swelling, and other symptoms
  • Counseling to cope with pain and to help with depression, anxiety, and stress
  • A nerve block to ease pain
  • Implants that deliver electrical impulses to the spine to manage pain
  • Surgery to destroy any nerves that are causing problems


There are no known guidelines to prevent CRPS.


International Research Foundation for RSD/CRPS 

U.S. Pain Foundation 


Health Canada 

RSD Canada 


Bruehl S. Complex regional pain syndrome. BMJ. 2015 Jul 29;351:h2730.

Complex regional pain syndrome (CRPS). EBSCO DynaMed website. Available at: . Accessed October 5, 2020.

Complex regional pain syndrome (CRPS). Merck Manual Professional Version website. Available at: Accessed October 5, 2020.

Complex regional pain syndrome fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: Accessed October 5, 2020.

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 09/2020
  • Update Date: 05/21/2021