Complex Regional Pain Syndrome (or Reflex Sympathetic Dystrophy)

Complex regional pain syndrome (CRPS) is a chronic pain condition that is thought to be the result of dysfunction in the central or peripheral nervous systems. Typical features include dramatic color and temperature differences of the skin of the affected body part, accompanied by intense burning pain, skin sensitivity, sweating, and swelling.

There are two general categories of CPRS, type I and II. Both have identical symptoms and clinical findings, however CRPS type I is commonly triggered by tissue injury without underlying nerve injury, whereas with type II there is a clearly associated nerve injury. CRPS can develop at any age and affects both men and women, although most experts agree it is more common in young women.

Other, more antiquated terms used to describe the same constellation of symptoms include “reflex sympathetic dystrophy syndrome” and “causalgia.”


The most prominent symptom is continuous, intense pain in the affected limb out of proportion to the severity of the injury (if an injury has occurred). If untreated these symptoms will worsens rather than improve over time. CRPS most often affects one of the extremities (arm, leg, hand, or foot) and accompanied by:

  • “Burning” pain
  • Increased skin sensitivity
  • Skin temperature changes: warmer or cooler compared to the unaffected extremity
  • Skin color changes: often blotchy, purple, pale, or red
  • Skin texture changes: shiny and thin, and sometimes excessively sweaty
  • Changes in nail and hair growth patterns
  • Swelling and stiffness in affected joints
  • Muscle weakness and loss of muscle mass
  • Decreased ability to move the affected body part

The pain may spread to affect the entire arm or leg, even though the triggering injury may have been only to a finger or toe. These changes can even begin to affect the opposite extremity. Symptoms may be heightened by emotional stress.


There is considerable variety in the severity and duration of symptoms. Experts believe there are three general stages associated with CRPS, which marks the progressive changes seen in the skin, muscles, joints, ligaments, and bones of the affected limb.

  • Stage one (Months 1-3) – Characterized by severe, burning pain, along with muscle spasm, joint stiffness, rapid hair growth, and changes to skin color and temperature.
  • Stage two (Months 3-6)- Characterized by worsening pain, swelling, decreased hair growth, cracked, brittle, grooved, or spotty nails, softened bones, stiff joints, and weak muscle tone.
  • Stage 3 (Months 6 and on) – The syndrome progresses to non-reversible skin and bone changes. Symptoms contiue to worsen and may affect the entire affect limb or the opposite limb. There may be significant muscle loss (atrophy), severely limited mobility, and involuntary contractions of the muscles and tendons that flex the joints. Limbs may develop deformities.


Researchers have not yet identified the cause or triggers for CRPS. The central and/or peripheral nervous systems through sympathetic pathways is thought to play an important role in the maintenance of the pain and subsequent development of the skin and bony changes. Other theories include an inflammatory immune response or a general disruption of the normal healing process. In all likelihood, there is not a single cause but rather multiple predisposing risk factors and an unknown trigger.


CRPS is diagnosed primarily through a detailed history and physical and observation of the typical signs and symptoms. Ruling out other similarly presenting diseases is important. Early in the course of disease with few and mild symptoms, it may be difficult for doctors to make a diagnosis of CRPS.

There are no specific diagnostic test to confirm CRPS, the most important role for testing is to help rule out other conditions. X-rays or a triple-phase bone scan may be used to identify changes in the bone and in blood circulation that would be suggestive of CRPS.


The prognosis for CRPS varies from person to person. Spontaneous remission may occur in certain people, while others may develop progressive symptoms of unremitting pain and crippling, irreversible changes despite of treatment. Some doctors believe that early treatment is helpful in limiting the disorder, but this belief has not yet been supported by evidence from clinical studies. More research is needed to understand the causes of CRPS, how it progresses, and the role of early treatment.


The goal of treatment is to relieve the painful extremity symptoms and prevent progression to advanced skin and bone changes. There is no cure for CRPS, however often times patients through treatment can be restored to living normal lives.

The following are the clinically accepted therapeutic options used:

  • Physical therapy: Goal is to restore mobility and function to the limb and prevent deformities or contractures. This is done though a gradually increasing exercise program. This should be performed under the care of a therapist training in treating CRPS patients.
  • Psychotherapy: CRPS often has profound psychological effects on people and their families. Those with CRPS may suffer from depression, anxiety, or post-traumatic stress disorder, all of which heighten the perception of pain and make rehabilitation efforts more difficult.
  • Medications: Several different classes of medications are used to treat CRPS, including topical analgesic drugs that act locally on painful nerves, skin, and muscles; antiseizure drugs; antidepressants, corticosteroids, and opioids. Unfortunately, to date there is no single drug or combination of drugs that has produced consistent long-lasting improvement in symptoms.
  • Sympathetic nerve block: Used for relief of severe pain symptoms. Techniques involve administration of medications near the appropriate nerves to block sympathetic nerve impulses.
  • Surgical sympathectomy: For relief of severe pain. This technique involves destroying the nerves involved in the signs and symptoms of CRPS. This effectiveness of technique is controversial among clinicians.
  • Spinal cord stimulation: The placement of stimulating electrodes next to the spinal cord provides a pleasant tingling sensation in the painful area.
  • Intrathecal drug pumps: These devices administer drugs directly to the spinal fluid. The local delivery of opioids and local anesthetic agents allows for lower drug dosing than those required for oral administration, thereby decreaseing drug side effects and increasing drug effectiveness.