Complex Regional Pain Syndrome

What is complex regional pain syndrome?

Complex regional pain syndrome is a chronic condition that causes long-lasting pain. Normally, pain is short-term and resolves as the body heals. But with this condition, pain doesn't fade with time. Instead, ongoing pain might get worse instead of better as days and weeks pass.


What causes complex regional pain syndrome?

Experts aren't sure what causes complex regional pain syndrome, but they believe that nerve damage is involved. In most cases, the condition occurs after some type of injury to the affected area, although this is not always the case.

Doctor’s view this disease as an abnormal response by the body that magnifies the effects of the injury. The nerve endings that control pain in an area that has been injured may become overly sensitive to the chemical messengers carried by the sympathetic nervous system. These chemical messengers, called catecholamines, may stimulate the pain and other symptoms.

What are the symptoms of complex regional pain syndrome?

If you have complex regional pain syndrome, you may have these symptoms:  

  • Persistent, burning pain in an arm, leg, hand, foot, or another part of your body
  • Pain can be mild or severe
  • Swelling
  • Sweating
  • Dramatic changes in skin color and skin temperature

How is complex regional pain syndrome diagnosed?

No specific test exists to diagnose complex regional pain syndrome with certainty. Your healthcare provider can diagnose it based on your medical history (such as having an injury) and the symptoms you have. But because several other conditions can cause similar symptoms, a careful physical exam is important. Sometimes tests are done to rule out some of these other conditions.

Your healthcare provider may suggest a sympathetic nerve block to find out if your sympathetic nervous system is causing your pain. This involves injecting an anesthetic into the nerves near the spine. If the nerve block helps your pain, your provider may give you a series of nerve blocks for ongoing relief.

How is complex regional pain syndrome treated?

There is no cure for complex regional pain syndrome, but sometimes the symptoms get better or stop on their own. Some evidence suggests early treatment, particularly with physical therapy, can help limit the disorder, but this has not yet been proven in clinical studies.

Treatment focuses on relieving the pain, typically with one or more pain medicines, antidepressants, antiseizure medicines, or oral steroid drugs. Other options include sympathetic nerve blocks, physical therapy, or electrical stimulation of the spinal cord or certain nerves. In severe cases, your healthcare provider may inject medicines directly into the fluid around the spinal cord via a drug pump or surgically But it is not clear how effective these treatments are.

Living with complex regional pain syndrome

The outcome in complex regional pain syndrome can vary widely, so it is important that the condition is diagnosed and treated as soon as possible to give you the best chance for a full recovery. Be sure to follow your healthcare provider's instructions for taking pain medicines and attending physical therapy or exercising if this is part of your treatment plan.

Physical therapy and exercise that keeps the painful limb or body part moving can often improve blood flow and lessen symptoms. It can also help improve the affected limb’s flexibility, strength, and function. If needed, occupational therapy can help you learn new ways to work and do daily tasks.

Complex regional pain syndrome is a painful condition that can bring on emotional or psychological issues for those affected and their families. People with this condition might have depression, anxiety, or post-traumatic stress disorder, all of which can make the pain seem worse and make rehabilitation efforts harder. Be sure to let your healthcare provider know how you are feeling, as there are often ways to help.

Some other types of therapies have been used to treat other painful conditions, such as behavior changes, acupuncture, chiropractic treatment, and relaxation techniques such as biofeedback, progressive muscle relaxation, and guided motion therapy. But it is not clear if they are helpful for this condition. Be sure to talk with your healthcare provider before starting any new type of treatment.

When should I call my healthcare provider?

If you have been diagnosed with complex regional pain syndrome and are being treated, be sure to talk with your healthcare provider about when you should call.

Your provider will likely advise you to call them if any of your symptoms get worse or if you develop any new symptoms.

Some people with this condition might need strong pain medicines, which can have their own side effects such as drowsiness, confusion, or changes in consciousness. Be sure to let your healthcare provider know if you have these or any other symptoms while taking pain medicines, as your doses might need to be adjusted.

Key points

  • Complex regional pain syndrome is a chronic condition that causes long-lasting pain. It is often caused by an overreaction in the body to a physical injury.
  • Symptoms include constant pain (ranging from mild to severe), sometimes along with swelling, sweating, and changes in skin color and temperature in the affected area.
  • Complex regional pain syndrome might resolve on its own over time, but in some people the symptoms can persist or even get worse. Common treatments include pain medicines, physical therapy, electrical nerve stimulation, and injecting an anesthetic into the nerves.

Next steps


  • Before your visit, write down questions you want answered.
  • Ask if your condition can be treated in other ways.

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