Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a greater than normal reaction of the body to an injury. The symptoms of CRPS vary in severity and how long they last. The main symptom is pain in an arm or leg, which is often burning, sharp, stabbing or stinging. Early treatment is often effective in treating symptoms. CRPS can sometimes cause severe problems and be difficult to treat.

What is complex regional pain syndrome?

Complex regional pain syndrome (CRPS) is a greater than normal reaction of the body to an injury. The cause of CRPS is not known. The nerves in the affected limb are much more sensitive than other nerves and this causes pain and tenderness in the affected area.

The pain usually starts after an injury but may occur without an injury. It usually affects an arm or a leg but can affect another part of the body. The injury may be severe, such as a broken bone or a damaged nerve, or may be a minor injury.

CRPS is not in your imagination but some emotional factors, like fear, worry or feeling depressed, can make the pain worse.

What causes complex regional pain syndrome?

There is often a history of an injury. The injury may be very minor such as a cut to the finger. The symptoms do not appear to be related to the severity of the injury. The injury may not be remembered, if it occurred at all.

CRPS can also start after other problems such as a head injury, stroke, heart attack or prolonged bed rest.

How common is complex regional pain syndrome?

CRPS affects about 1 in 4,000 people each year. CRPS can affect any age but is more common between the ages of 40 and 60 years. It can also affect children and the number of CRPS cases among teenagers and young adults is increasing. Although CRPS can start after a minor injury, it is more common after an injury to a nerve or after a fracture.

What are the symptoms of complex regional pain syndrome?

The symptoms of CRPS vary in severity and how long they last. Symptoms usually begin within one month after an injury or after having to stay in bed for a long time. The main symptom is pain in the arm or leg, which is often burning, sharp, stabbing or stinging. There may also be tingling and numbness.

The symptoms are usually much worse than you would expect after the injury. CRPS pain continues after the original injury has healed. The symptoms are often severe and have a big effect on day-to-day activities. The pain may spread to other limbs. The pain is long-lasting, and gets worse rather than better with time. Staying in bed and not moving around may make the pain and stiffness worse.

Movement may be limited, both because of the pain and because joints can be stiff. The muscles may become weak. Other muscle problems may occur and include sudden and severe spasms, tremors, severe jerking and other abnormal movements.

The pain and other symptoms often spread beyond the site of the original injury. The symptoms may spread gradually over the affected limb or suddenly affect the opposite limb.

Many patients say that their limb 'feels strange'. It can feel as if it does not belong to the rest of the body and as if it is not your own limb. Sometimes the limb feels bigger or smaller than normal.

As well as pain, the affected area may have other symptoms such as:

  • Skin sensitivity: the skin may become oversensitive to light touch.
  • Allodynia: this means that you feel pain even after just a gentle touch, such as clothes brushing your skin or even air blowing on your skin. This may be felt as severe pain.
  • Swelling: may occur over the painful region.
  • Temperature differences between opposite sides: the affected arm or leg may often be warmer or cooler and the temperature may keep changing.
  • Abnormal sweating.
  • Skin changes:
    • Abnormal skin changes may occur, like 'goosebumps' and skin rashes.
    • There may be changes in the skin colour of the affected limb.
    • Skin infections can occur and can be very severe.
    • Your skin may become shiny, dry or scaly.
  • Hair changes: hair may become coarse but then become thin.
  • Fingernail or toenail changes: nails in the affected area may become brittle (crumbly or break easily) and grow faster at the beginning and then slower.

Psychological symptoms

Psychological symptoms may include:

  • Difficulty relaxing
  • Feeling less confident in yourself
  • Feeling unable to cope
  • Difficulty getting or accepting support from friends or family
  • Depression (this is common)

Are there any tests for complex regional pain syndrome?

The diagnosis is usually made by an examination by a specialist. The diagnosis may be difficult, especially in the early stages. It is very important to diagnose CRPS as early as possible because early treatment can prevent the arm or leg becoming weak because you can't use it properly.

There are no specific blood tests or other investigations. However, investigations may be important to rule out any other cause for your symptoms.

Are there any treatments for complex regional pain syndrome?

Early treatment is often very effective in treating symptoms. Treatment includes helping you to understand the condition and what you can do to help yourself. Other treatments may reduce pain, or be physical treatments like physiotherapy, or be support and treatment for any psychological difficulties. The right treatment for CRPS is different for each person.

Do I need to see a specialist?

Your GP will usually refer you to see a specialist so that:

  • The diagnosis of CRPS can be confirmed.
  • Other causes for your symptoms can be ruled out.
  • You can be helped with with a treatment plan to control the difficult symptoms, including pain and distress.
  • Treatment to keep you as active as possible can be provided, including physiotherapy.

If your symptoms are more severe and don't improve with treatment then you may need to be referred to a Pain Clinic or another specialised unit for further treatments. Because of the different symptoms with CRPS, you may need to see other teams of doctors, such as:

  • a bone specialist (orthopaedic specialist)
  • a bone and joint specialist (rheumatologist)
  • a nerve specialist (neurologist) and
  • a skin specialist (dermatologist)


Rehabilitation should be considered for anyone with CRPS and should be started early. Support and treatment from a physiotherapist and an occupational therapist are very important.

Rehabilitation includes helping you to use the limb with gentle exercises and helping to make the limb less sensitive. Other treatments help you to use the limb more normally and reduce any fluid swelling (oedema).

Specialised units may also use more specialised treatments such as mirror visual feedback and graded motor imagery.

Medication treatment

Medicines can be used to help reduce the pain and help you to sleep. Simple medicines for pain relief such as non-steroidal anti-inflammatory drugs (NSAIDs) are used first and the strength and doses of the medicines are increased until the pain is well controlled.

If the pain is not reduced then other types of medicine are used - for example, tricyclic antidepressants or gabapentin. See the separate leaflet called Neuropathic Pain.

Medications may also be needed for depression.

Pamidronate is a bisphosphonate medicine that is given by slow injection into a vein. It may be given as a one-off treatment if you have had CRPS for less than six months.

Psychological support and treatment

Sometimes psychological treatment can help to reduce distress. A psychological assessment by an expert in chronic pain may help to identify problems that can be helped. Psychological interventions (including cognitive behavioural therapy and relaxation techniques) can help the psychological difficulties associated with CRPS.

What are specialised treatments for CRPS?

There are two particular specialised CRPS treatments:

Pain management programme (PMP): this is a programme to help you to improve your quality of life and manage your pain better. PMP is given to a group of people with CRPS and includes help from different health professionals, including doctors, physiotherapists, occupational therapists and psychologists.

Spinal cord stimulation (SCS): this involves using a fine wire which is placed close to the nerves in your back and is connected to a 'stimulator'. The wire is kept in place for a short time and, if it works well, an operation can be done to make it permanent. The SCS can be taken out when it is not needed anymore.

Research shows that in some patients these treatments can work very well. Specialised centres may also use other treatments. The evidence for these specialised treatments is not completely proven but many people with CRPS have found one or more of them very helpful.

What is the outcome (prognosis)?

CRPS is very variable both in how severe the symptoms are and how long the symptoms last for. CRPS may be mild and get better by itself or with treatment. In some people, CRPS can cause severe symptoms and last for many years. There is no way of knowing whether your symptoms will get better, and when. Even if you have CRPS for several years, the rest of your body will continue to work as normal.

Some people with CRPS have times when the symptoms are bad (exacerbations) and other periods of time when the symptoms are much fewer or even disappear (remissions). The periods of exacerbation may last for weeks, months or years.

If it is not diagnosed and treated, CRPS can spread and affect other limbs. This makes CRPS much harder to treat.

Can complex regional pain syndrome be prevented?

People experiencing fractures have been advised to have a good intake of vitamin C but there is no proven way that CRPS can be prevented.