Overview of Reflex Sympathetic Dystrophy (RSD)/Complex Regional Pain Syndrome (CRPS)

Complex regional pain syndrome (CRPS), formerly called reflex sympathetic dystrophy (RSD) and causalgia, is a chronic, painful, and progressive neurological condition that affects the skin, muscles, joints and bones. The syndrome usually develops in an injured limb, such as a broken leg, or following surgery.

Woman in Pain - Masterfile Image

However, many cases of CRPS involve only a minor injury, such as a sprain or strain. And in some cases, no precipitating event can be identified.

RSD/CRPS is characterized by various degrees of burning pain, excessive sweating, swelling, and sensitivity to touch. Pain may begin in one area or limb and then spread to other limbs. In some cases, symptoms of RSD/CRPS diminish for a period of time and then reappear with a new injury.


Two types of RSD/CRPS have been defined:

  • Type 1 (CRPS I)—without nerve injury
  • Type 2 (CRPS II)—with nerve injury

Both types of RSD/CRPS share the same signs and symptoms.

Incidence and Prevalence of RSD/CRPS

Millions of people in the United States may suffer from RSD/CRPS. This chronic pain syndrome affects both men and women, and also occurs in children. It can occur at any age, but usually affects people between the ages of 40 and 60 years. According to most experts, CRPS is more common in young women.

The National Institute of Neurological Disorders and Strokes (NINDS) reports that 2–5 percent of peripheral nerve injury patients and 12–21 percent of patients with paralysis on one side of the body (hemiplegia) develop reflex sympathetic dystrophy as a complication. The Reflex Sympathetic Dystrophy Syndrome Association of America (RSDSA) reports that the condition develops after 1–2 percent of bone fractures.

Publication Review By: Eric M. Schreier, D.O., F.A.A.P.M.R.

Published: 30 Dec 1999

Last Modified: 02 Oct 2015