Complex regional pain syndrome (CRPS) is a common and debilitating chronic pain disorder that usually occurs after a minor injury to the hand or foot. It can also occur after more significant traumas, for example surgery to the hands, feet or to other parts of the body like the knees or shoulders. It has previously also been called Causalgia, Reflex Sympathetic Dystrophy (RSD), and Reflex Neurovascular Dystrophy (RND). It is still not entirely certain why and how CRPS occurs, but we do know that it can be a disabling and excruciatingly painful condition that in some cases can last a long time.

CRPS is characterised by certain changes to the painful area which might include exquisitely sensitive skin (where even a light brush could be painful), swelling, redness, warmth, and changes to the way the hair and nails grow. The hand or foot may not function correctly and cramps can occur. Later on, the area can look mottled and feel cold.

The mainstays of CRPS treatment are early detection and aggressive treatment by pain specialists.


It is not clear what causes CRPS.  There must first be a triggering injury like a ligament strain, sprain, laceration, or surgery.  The injury does not need to be severe to trigger CRPS.  Once triggered, changes in the function of nerves occur.  Nerves carry sensation (feeling and touch), motor information (telling muscles how to move) and drive other functions like blood flow, which affects sweatiness and colour changes within the skin. This can lead to stiffness and weakness too.

Complex Regional Pain Syndrome is also categorised into two types, which have similar symptoms, but different causes. CRPS Type 1 occurs after an injury that has not directly affected the nerves in the limb, while the less-common CRPS Type 2 follows an injury with evidence of nerve damage.


Anyone can get CRPS after an injury to their arm or leg or other part of the body. 

If someone has already had CRPS they are more likely to get it again with another injury. There may also be a genetic link to the occurrence of CRPS in families.

CRPS occurs in about 5:100,000 people. The upper limbs are generally more affected than lower limbs. The arm is affected in 60% of cases and the leg in 40%. It can affect more than one limb and can even appear on the opposite limb.


CRPS is characterised by a number of symptoms:


People with CRPS pain report reduced or painful movement, causing, for example,  the inability to make a fist. Pain may affect the arm and shoulder, leg, knee, foot, or hand.


People with CRPS report changes in the sensation of the skin.  For example, the skin can feel very sensitive, painful to even gentle touch, or numb.


People with CRPS notice altered skin temperature, colour, and sweatiness, changes in hair growth and sometimes odd features like very fast or slow nail growth.


Pain specialists can diagnose CRPS according to a set of criteria called the Budapest Criteria, which depend on the number and severity of symptoms. Sometimes medical tests are done to make sure there are no infections or problems with the bones.


When CRPS is suspected by a treating team the most important thing is to pay attention to the symptoms and to never assume they will resolve on their own.  Although it does happen in some patients, the most basic rule of pain management is to manage pain early and aggressively using many different modalities. This is to prevent acute pain becoming chronic pain and for the best chance of a total recovery.  Early referral to a pain specialist is a vital step for getting the right treatment started as quickly as possible.


Patients with CRPS require early assistance from specialist therapists with backgrounds in physiotherapy and occupational therapy.  These therapists use a host of techniques to improve the motor functions of the affected part of the body, aid with reduction in swelling and skin sensitivity and should be a part of management throughout treatment. This is a vital step in recovery.


There are a number of different pain injection treatments (interventions) that aid patients with CRPS.  These include nerve block treatments that target nerves that cover the affected limb. Nerve blocks might be stellate blocks, sympathetic blocks, nerve root blocks and sometimes even pulsed radiofrequency ablation. These treatments should be used in conjunction with medications and pain therapy.


Chronic pain is an exhausting condition that understandably leads to poor sleep, mood disturbance like anxiety and depression, and reduced function.  It is imperative that people struggling with chronic pain are frank and open about the distress they experience.  Trained pain specialist psychologists are invaluable in helping patients manage these situations and cope with the pain. Sometimes patients require a more formalised cognitive behavioural therapy (CBT).


Most patients report significant improvement with the treatment options listed above, but this is not always the case.

It is vital that symptoms are not ignored and that referral to a pain specialist occurs quickly.  Further options are available and are often very effective in managing severe or prolonged CRPS:


This strong pain-relieving medication is given as an infusion during a week-long hospital admission.  This gives better control, allowing intensive physical therapy with the aim of improved function and pain relief.


This technique involves an implanted pacemaker for pain nerves and can be profoundly effective for CRPS that has not responded to more conservative treatments.  Spinal cord stimulation involves a trial phase, so before anything permanent is considered the treatment can be trialled to indicate how successful it might be.  It is rare in medicine to have an opportunity like this. It has been suggested that spinal cord stimulation should be used early in the treatment of some forms of CRPS.

For further information on spinal cord stimulation, please refer to our ebook.


High dose of Vitamin C can prevent this problem in some people. Most pain specialists will advise taking 500mg of Vitamin C daily for two months following a minor injury of the wrist.

If you have any questions, just ask.

We recognise that your pain affects your ability to do the things that make you who you are. We manage the impact that pain has on your world.
— Dr Nick Christelis