Complex Regional Pain Syndrome (CRPS)

Complex Regional Pain Syndrome (CRPS) is a condition that causes lasting pain, swelling, and sensitivity, usually in an arm or leg, after an injury like a broken bone, surgery, or even a small sprain. In the past this condition was called reflex sympathetic dystrophy (RSD). For reasons doctors don’t fully understand, in CRPS the body’s nervous system overreacts to the injury, causing intense pain that lasts much longer than it should. It often starts in one specific area, like a hand, foot, arm, or leg, but can spread. CRPS is rare and but it can happen to anyone. Complex regional pain syndrome is more common in women and usually affects people between their 30s and 50s, though teenagers and older adults can also get it.

Diagnosing CRPS

Complex Regional Pain Syndrome (CRPS) is diagnosed by a doctor based on a patient’s symptoms and physical exam. There isn’t a specific test for CRPS, so the doctor looks for signs like ongoing pain, swelling, changes in skin color or temperature, and excessive sensitivity in the affected area. They may also use imaging tests, like X-rays, bone scans, or MRIs, to check for changes in the bones or tissues that could help confirm the diagnosis. Since some other conditions can look similar to CRPS, the doctor may rule out other problems before deciding it’s CRPS.

Classification of Complex Regional Pain Syndrome

Complex Regional Pain Syndrome (CRPS) is usually divided into two main types:

• CRPS Type 1 is the most common form and occurs without a clearly identifiable nerve injury. It often develops after an injury such as a fracture, sprain, or surgery.
• CRPS Type 2 occurs when there is a known injury to a specific nerve.

Although the causes are slightly different, both types can produce similar symptoms, including severe pain, swelling, stiffness, skin color changes, temperature changes, and difficulty moving the affected arm or leg.

Doctors may also describe CRPS as either “warm” CRPS or “cold” CRPS. Warm CRPS is more common early in the condition and is associated with redness, warmth, and swelling due to increased inflammation. Cold CRPS is more often seen in longer-standing cases and may cause the affected area to feel cool, stiff, pale, or bluish. These classifications help doctors better understand the condition and guide treatment decisions.

Treating Complex Regional Pain Syndrome

Treatment for Complex Regional Pain Syndrome (CRPS) focuses on reducing pain, improving movement, and helping the affected arm or leg return to normal function. Early treatment is very important because CRPS is often easier to manage before stiffness and chronic pain become severe. Physical therapy is usually one of the most important parts of treatment. Gentle movement exercises help maintain flexibility, strength, and circulation while preventing the limb from becoming stiff or weak. Occupational therapy may also help patients regain the ability to perform everyday activities. Medications may be used to reduce pain, nerve irritation, or inflammation and can include anti-inflammatory medications, nerve pain medications, or occasionally other specialized treatments. In some patients, treatments such as nerve blocks, desensitization therapy, mirror therapy, or psychological support may also be helpful.

The main principles of treating CRPS are to:

• Encourage gradual movement
• Control pain
• Avoid allowing the affected limb to become overly protected or unused

Patients are encouraged to remain as active as possible within reasonable limits because prolonged immobility can worsen symptoms. Treatment usually works best when multiple approaches are combined, including physical therapy, pain management, education, and emotional support. Recovery can take time, but many patients improve significantly with early recognition, consistent rehabilitation, and a gradual return to normal activity.

Edited by Stephen Pinney MD, May 26th, 2026.