Complex regional pain syndrome (CRPS)

What is complex regional pain syndrome?

Complex regional pain syndrome (CRPS) is a condition that causes severe pain which won't go away. It usually affects just one arm or leg and often follows an earlier injury to the limb. However, the body's reaction to the injury is much stronger than usual and may affect more of the limb than the original injury did.

Doctors sometimes make a distinction between two types of CRPS:

  • CRPS type 1 follows an injury such as a fracture or sprain but with no nerve damage and is sometimes referred to as reflex sympathetic dystrophy (RSD) or Sudeck's syndrome.
  • CRPS type 2 follows damage to a nerve in the limb and is sometimes referred to as causalgia.

Anyone can be affected by CRPS, including children. It most commonly affects the hand and wrist, foot and ankle, or knee, although sometimes the whole limb can be affected.

Should I see a doctor?

We would always recommend you see a doctor if you have pain that won't go away. CRPS is rare but it's important to get the right diagnosis so that appropriate treatments can begin. Research shows that treatment for CRPS is usually most effective when it’s started early on.


Pain is the main symptom of complex regional pain syndrome (CRPS). It may be a burning, stabbing, stinging or throbbing pain. The affected limb is often extremely sensitive to touch. Even light stroking or the weight of clothing can cause severe pain.

The painful area is often swollen (which can lead to stiffness). After a time, the muscles in the affected limb may weaken. Movements may be difficult to control, shaky or jerky.

You may notice colour or temperature changes in the affected areas. Or the skin of the affected area could look more red or blue than normal, and may appear mottled or unusually shiny.

These changes can vary a great deal sometimes during the course of a day.

Some people notice stiffness, changes to the hair or nails, or more or less sweating in the affected limb. Many people say the limb 'feels strange' or it feels larger or smaller than the normal limb.

People with CRPS become anxious or depressed – this is normal for anyone with long-term (chronic) pain and needs to be dealt with. Others have negative feelings about the affected limb.

Read more about managing pain.


We don’t yet know exactly what causes complex regional pain syndrome (CRPS) but a fracture or other injury sometimes seems to act as a trigger. Symptoms of CRPS start within a month of the injury.

It's thought that the nerves of the affected limb are much more sensitive than normal and that pain pathways between the affected limb and the brain may change so that pain continues long after the original injury has healed. The pain and other symptoms also affect a wider area than the original injury.

More rarely, CRPS can occur after other problems such as a stroke or multiple operations to a limb. In other cases (about 1 in 10) it develops without any obvious trigger factor.

How will complex regional pain syndrome (CRPS) affect me?

It’s difficult to predict how complex regional pain syndrome (CRPS) will progress in any one person, but early diagnosis and treatment are helpful.

Many people find their CRPS settles over a few weeks or months with good rehabilitation therapy. However, if you've had symptoms for more than six months then it's more likely that you'll still have some pain even after treatment. Some people find that other symptoms improve even if the pain continues.

CRPS often affects a wider area than any previous injury and it may affect the whole limb. Occasionally, people who’ve had CRPS in one limb may develop it in another, but this is relatively unusual. It's also possible for symptoms to return in people who've had a previous improvement in symptoms.

Even if you have CRPS for a long time, it will not damage the body's tissues. However, you should try not to alter your posture to adapt to the painful limb, as this can sometimes lead to secondary problems in other parts of the body.


There’s no specific test that will confirm you have complex regional pain syndrome (CRPS). Doctors mainly base the diagnosis on your symptoms and a physical examination, although tests may be used – sometimes to rule out other conditions:

  • An x-ray or bone scan of the affected limb may show thinning of the bone (osteoporosis) or other abnormalities.
  • Blood tests may help to rule out infection or autoimmune conditions such as rheumatoid arthritis.
  • Magnetic resonance imaging (MRI) scans may help to rule out problems with the bones or other tissues.
  • Regional anaesthesia, or blocking of the sympathetic nervous system with a local anaesthetic, is occasionally used as a diagnostic test. If this block eases the pain, then it’s likely that you have CRPS.

The International Association for the Study of Pain have set criteria, called the Budapest criteria, to help with diagnosis. These take into account the following symptoms:

  • unusual sensitivity to touch
  • differences in skin colour or temperature between the affected limb and the normal one
  • swelling or unusual sweating in the affected limb
  • reduced range of motion, loss of function, or changes in the hair, skin or nails of the affected limb.

If your GP is in any doubt about the diagnosis you may be referred for a specialist opinion.

Once you've been diagnosed with CRPS it's likely that you'll be referred to a specialist pain clinic for treatment – usually at a local hospital.


There's no single treatment available that will help everybody with complex regional pain syndrome (CRPS) but movement – as far as possible – is the most important aim. This usually involves a combination of physical rehabilitation therapies and pain-relieving medication. You will also be offered advice on managing the condition and may be offered psychological therapies to help you develop coping strategies.

Rehabilitation therapies

Rehabilitation therapies play a very important part in the treatment of CRPS and are usually most effective when started early.

The most important goals of rehabilitation are to restore as much function as possible and to improve quality of life.

Rehabilitation therapies probably won't stop the pain completely but will help you use the limb more normally. They should also help to avoid secondary problems like weakening of the muscles through lack of use.

Most therapies will begin very gently to avoid a flare-up of your symptoms, and you’ll probably need pain medication to help lessen the pain so that you can start the therapies. You'll need to build up the length of time and intensity of your therapies gradually, even if progress seems slow at times.

Rehabilitation will involve elements of physiotherapy and occupational therapy, but in some areas you will see the same person for both.

Managing your symptoms


Regular exercise is important for your general health. Your instinct may be to avoid exercise if you're in pain, but you should still try to do a little each day in addition to the specific exercises you've been shown for your painful limb.

Walking and swimming are good low-impact exercises that will help keep you fit and healthy, maintaining strength and function in the affected limb without putting too much strain on it.

Read more about exercise and arthritis.


Although there’s no direct link between your diet and CRPS, keeping to a healthy weight and eating a sensible, balanced diet is important for your overall wellbeing.

There's some evidence that high doses of vitamin C may reduce the risk of developing CRPS following an operation, and it's been suggested that vitamin C may be helpful in the early stages of CRPS.

Read more about diet and arthritis.

Living with complex regional pain syndrome


Most people with CRPS are able to continue in their jobs, although you may need to make some alterations to your working environment, especially if you have a physically demanding job.

Speak to your employer's occupational health service if they have one, or your local Jobcentre Plus can put you in touch with Disability Employment Advisers who can arrange work assessments. They can advise you on changing the way you work and on equipment that may help you to do your job more easily. If necessary, they can also help with retraining for more suitable work.

Read more about work and arthritis.

Dealing with stress

Living with a long-term condition like CRPS can lower your morale and may affect your sleep. It’s important to tackle problems like these as they could lead to depression and will certainly make the CRPS more difficult to cope with.

It often helps to talk about negative feelings, so it could be useful to speak to your healthcare team, or your family and friends. Support groups are also available, your doctor may be able to tell you about organisations in your area.

Find out more about coping with fatigue or long-term pain.

Cath's story

Cath has lived with severe complex regional pain syndrome (CRPS) for many years. As well as having to cope with crippling, constant pain, she has very bad allodynia – where those with the condition can’t bear for the affected limb to be touched or even slightly brushed. In Cath’s case this was her right arm.

Cath, from Sheffield, was one of the first patients to take part in a study into CRPS and spent two three-week periods undergoing intensive rehabilitation at the Royal National Hospital for Rheumatic Diseases (RNHRD) in Bath.

She also took part in a study by Dr Helen Cohen, which involved taking writing tests and looking at optical illusions. The study aimed to shed new light on the role of the brain in CRPS and hopes to explain the sometimes bizarre symptoms sufferers experience.

‘One of the big problems I have is that I can’t go to the normal doctor and tell him what has happened because they would say I’ve flipped,’ explains Cath. ‘I trapped my hand in a till at work but it was my mouth and face that were in agony. I had a tooth out and my arm swelled up. One of the tests I had in Bath involved chilli cream being rubbed on the inside of my right wrist and I felt the pain and swelling on my left wrist. You try and explain that. I end up getting quite emotional about it.

‘I want to feel reassured by this research because many doctors put my problems down to being psychological. This research is undoubtedly progress; but equally I feel very confused still.’

Cath needs constant painkillers and muscle relaxants to get through the days and, despite periods of depression, remains positive that as researchers find out more about this baffling condition, effective treatment will finally follow.

She said: ‘I still find it very isolating. It’s not something you can talk about to a neighbour if the doctor doesn’t know what I’m talking about. It’s a great relief to know that they are doing something about it in Bath.’

You can read more of our supporter stories on our Your stories page.