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What is complex regional pain syndrome?

What is complex regional pain syndrome?

Complex regional pain syndrome (CRPS) is a medical term that broadly describes excessive and prolonged pain and inflammation, usually in an arm or leg (though it can affect any part of your body).
Described by the NHS as a poorly understood condition (i), CRPS has been a known neurological disorder for many years – the charity CRPS UK says it was first observed during the American civil war, when it was known as causalgia (ii).
CRPS usually develops after an injury. However the pain it causes is typically far more severe and debilitating than you’d expect from the injury in question, plus it usually lasts much longer and may spread to affect a larger area (for instance, the pain could start in a finger and spread to the entire arm). In about seven per cent of cases, CPRS symptoms spread to a different part of the body altogether (iii). However in around one in 10 (iv) cases CRPS can develop in people who haven’t sustained any injury at all.
The NHS says it’s difficult to estimate how common CRPS is, as many cases may go undiagnosed or be misdiagnosed – though it adds that the condition is thought to be fairly uncommon (i). Patient UK, however, says CRPS affects around one in 4,000 people every year (v). Anyone of any age can be develop it, including children, though CRPS is thought to be rare in those younger than six years of age. The condition is also more common in women than men by a ratio of 3.5:1 (vi). Women with CRPS are also more likely to experience more severe symptoms than men.
Experts have different opinions about the most common age for developing CRPS: the National Institute of Neurological Disorders and Stroke in the US claims it has a peak age of around 40 (vii), while the Reflex Sympathetic Dystrophy Syndrome Association (a US-based non-profit organisation) says the highest incidence is in women aged 60 - 70 years (viii).

Types of CRPS

Nowadays in the UK experts don’t usually differentiate between types of CRPS, though some doctors may mention the following:

  • CRPS type 1 is typically triggered by a mild injury such as a sprain, where there is no identifiable nerve damage (this may sometimes also be called reflex sympathy dystrophy or Sudeck’s syndrome)

  • CRPS type 2 follows a more serious injury that has damaged a major nerve – a bone fracture, for instance

The good news is that most cases of CRPS tend to be mild and settle over a few weeks or months with the right treatment. Indeed, according to Patient UK, studies suggest 74 per cent of cases resolve within a year (ix).
Some people, however, experience prolonged pain and other symptoms despite having treatment – a Royal College of Physicians report says around 15 per cent of people with CRPS have unrelenting pain and physical impairment two years after the start of their symptoms (iii). Understandably this can lead to severe physical and psychological problems. Nevertheless, professional diagnosis and treatment is important, since it’s possible that CRPS could spread to all your extremities and cause complete incapacitation if it isn’t treated correctly.

What are the symptoms of CRPS?

CRPS symptoms usually start within a month of an injury or other triggering event, the main symptom being pain. The experience of pain can vary from one person with CRPS to another, with the most common pain sensations including stinging, burning, tearing, squeezing and stabbing. Most people with CRPS experience periods when their pain gets better and others when it gets worse (these are known as flare-ups). For some, however, the pain can be constant.
In around 60 per cent of cases CRPS affects an arm (ix). However – as the word ‘complex’ suggests – there’s often more to CRPS than just pain, with other possible symptoms including the following:

  • Increased skin sensitivity (the affected area may become oversensitive even to the lightest touch)

  • Pain caused by a non-painful stimulus (this means you feel pain when your skin comes into contact with something that doesn’t normally cause pain  – for instance, the feel of your clothes brushing against your skin may be very painful)

  • Unusual sensations (one example is that you may feel as if the affected body part – usually a limb – doesn’t belong to the rest of your body, or that it’s bigger or smaller than the other corresponding limb)

  • Numbness and tingling (including pins and needles)

  • Swelling

  • Joint stiffness leading to mobility problems

  • Sleep difficulties such as insomnia 

  • Skin in the affected area that’s hotter or colder than the rest of your body

  • Abnormal sweating (including cold sweats) 

  • Skin changes such as rashes, goosebumps, dryness, a shiny or scaly appearance, or a change in colour (it may, for example, look red, pale, grey, blue, purple, blotchy or streaky)

  • Skin infections such as open sores or ulcers

  • Changes to body hair in the affected area (for instance, hair that first becomes coarse and then fine)

  • Nails becoming more brittle or grooved

  • Muscle problems such as weakness, spasms, tremors and involuntary jerking as well as atrophy (muscle wasting) and contractures (where muscles become shorter and cause a restricted range of movement)

Psychological symptoms caused by CRPS can include depression, being unable to relax, lack of confidence and feeling you can’t cope. The strain of living with the pain of CRPS can also lead some to have suicidal thoughts, especially while having a bad flare-up.
If you are having or have had suicidal thoughts recently, see your GP as soon as possible or call the Samaritans on 116 123 (email You can also read our article How to cope with suicidal feelings for further advice.
Meanwhile if you have any type of persistent pain that stops you from doing your everyday activities, see your GP as soon as possible, as early treatment for many pain conditions (including CRPS) may be more effective than delayed treatment.

What causes CRPS?

Nerve damage is thought to be behind most cases of CRPS, even when no nerve injury can be found. According to the National Institute of Neurological Disorders and Stroke, most CRPS illnesses are caused by damage to or improper function of small peripheral nerve fibres called C-fibre nerve fibres, which transport pain messages to the brain (vii). This makes the nerve fibres far more sensitive, which makes pain worse.
Damage to these nerve fibres is believed to be caused by injury, with some the most common types including:

Having surgery is also thought to cause CRPS in some people, while others may develop the condition when one of their limbs is immobile for any length of time (for instance, when a bone is broken and the limb is in a cast). Some experts also suggest CRPS can develop after an illness such as a stroke or heart attack (vii). 
We still don’t know why some people develop CRPS after one of these injuries or events and others don’t, though neurological, immune and genetic factors may be involved. Poor circulation and poor nerve health may also play a part, plus CRPS may have something to do with immune system dysfunction as the condition is thought to be more common in people with other inflammatory and autoimmune conditions such as asthma (vii).

Are you at risk?

Despite the fact that we still don’t know exactly what causes CRPS, we do know that some things may increase your risk of developing it after having an injury. These things include:

  • Gender (women are more likely to develop CRPS than men)

  • Age (CRPS is less likely to develop in people under 40 years of age)

  • Type of injury (45 per cent of CRPS cases develop after a bone fracture and 18 per cent after a sprain (ix))

  • Health conditions such as psychiatric disorders, substance use disorder and headache disorders have been linked with a higher risk of CRPS (x), as have fibromyalgia and rheumatoid arthritis (ix) 


How is CRPS treated?

There are no specific tests that diagnose CRPS, but if your doctor things you may have developed it they’ll usually refer you to a specialist who can perform tests to rule out other conditions with similar symptoms. These include nerve entrapment, deep vein thrombosis, thrombophlebitis and carpal tunnel syndrome
Treating CRPS aims to help you to manage the symptoms, since there’s no known cure for the condition. According to the NHS the four main treatment areas include (xi):

  • Education and self-management (helping you understand your condition and learning what you can do to help manage it)

  • Physical rehabilitation (physical therapy and other techniques to keep you moving and reduce your risk of developing long-term physical problems)

  • Pain relief (several medications for reducing pain may be used, including anti-inflammatory drugs and tricyclic antidepressants, plus a treatment called spinal cord stimulation if pain drugs aren’t helpful)

  • Psychological support (therapies such as cognitive behavioural therapy – CBT – may help you to manage long-term pain)

According to Patient UK there’s a lack of high-quality evidence for the effectiveness of most individual treatments, though early treatment that looks at the whole problem is often effective – with the right treatment being different for each individual (v).

Living with CRPS

Some of the things you may learn about managing your symptoms include the importance of staying active and eating healthily to keep your weight under control. Pain can persuade even the most keen exerciser to be less active, but it is really important to do a little gentle exercise every day, on top of the exercises your physical therapist will teach you.
For instance, low-impact exercises such as walking and swimming may help keep your muscles and joints strong and working well without putting too much strain on them, or you could try some gentle yoga or t’ai chi. Meanwhile try to avoid sitting or lying down for long periods – aim to stand up and walk a few steps or more every hour or so during the day. Try to do this even when you’re having a flare-up, as inactivity could make your pain worse. However try to learn how to pace yourself when you do anything physical – little and often is better than doing too much all at the same time.
There isn’t a specific diet you should follow if you have CRPS, just try to stick to foods that are healthy and nutritionally balanced whenever you can, and aim to eat at least five portions of fruit and vegetables every day. Eating healthily will boost your overall health and wellbeing, plus it can help you maintain a healthy weight. If you need help with your diet, ask your GP or specialist about being referred to a dietitian.
Some of the other self-care measures you may find beneficial include the following:

  • Learn to destress – talking to a trusted friend or family member may help you deal with the symptoms of CRPS when you feel things are getting on top of you; meanwhile try to set aside some time every day to relax or do something that helps make you feel calmer

  • Get involved with other people who know what you’re going through via social media –CRPS UK has Facebook and Instagram pages where the charity posts about news and events. You can also join its private Facebook forum to make contact with other people who have the condition 

  • Try distracting yourself by doing things you enjoy and find absorbing, such as hobbies and other interests – getting involved in something can help you feel more like you’re in control of your life

  • Take steps to improve your sleep if you need to, as having pain can make it difficult for you to get a good night’s rest. There’s lots of advice on getting a better night’s sleep in our guide to sleep and insomnia 

Meanwhile some of the nutritional supplements you may find useful include:
PEA   Short for palmitoylethanolamide, PEA is a fatty acid produced naturally by the body and found in all cells, tissues and fluids including the brain. You can also get it in foods such as soya beans, peanuts, eggs, flaxseed and milk.
An endocannbinoid-like chemical that belongs to a family of fatty acid compounds called amides, PEA is often described as an alternative to CBD, as both substances are thought to have similar properties including the ability to reduce pain and inflammation. Researchers, however, suggest PEA is safer than CBD, since it has been studied more extensively and has a more robust safety profile (xii) with no known side effects (xiii). A review of 16 clinical trials and meta-analysis also confirms PEA has painkilling actions (xiv).
Magnesium   This important mineral is found naturally in the body and is needed for more than 300 biochemical reactions, including muscle and nerve function. While there is a lack of strong clinical evidence claiming taking magnesium supplements may help specifically with the pain of CRPS, studies suggest it could be useful in a range of other pain conditions such as fibromyalgia, headaches, migraines, period pain, post-herpetic neuralgia, diabetic neuropathy and back pain (xv) – though experts admit research is still at an early stage and more large-scale studies are needed to better understand how magnesium may help manage pain. 
Vitamin C   This may also have a role in pain management, including that for CRPS, claim researchers writing in the Journal of Translational Medicine (xvi). In their paper The role of vitamin C in the treatment of pain: new insights, the experts suggest theres evidence vitamin C may help with a number of other pain conditions too, including post-herpetic neuralgia and cancer. Another study suggests vitamin C may help prevent CRPS in people who have fractured their wrist (xvii), while a review of studies concludes taking a daily vitamin C supplement may reduce the development of CRPS in people who’ve had a fracture or surgery (xviii).

Want to find out more?

The pain and disability associated with CRPS can be extremely difficult to live with. But medical treatments – including psychological therapies – as well as self-care measures can help you cope. To find out more about coping with a range of other pain conditions, visit the pain section of our pharmacy health library



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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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