Complex Regional Pain Syndrome (CRPS)

Complex regional pain syndrome (CRPS) is a form of chronic pain that usually affects an arm or a leg and most often appears after an injury, fracture, or surgery. Its most characteristic feature is that the pain is far more severe and persistent than would be expected from the original injury. The pain is frequently accompanied by swelling, changes in skin color and temperature, differences in sweating, and heightened sensitivity. ^[1][3][4]

This guide explains what CRPS is, its symptoms, its causes, how it is diagnosed (the Budapest criteria), and especially the role of physiotherapy within multidisciplinary care, drawing on reputable sources. CRPS is a sensitive neurological/pain condition; this content does not provide a diagnosis and is not a substitute for a treatment plan. Its goal is to help you understand the condition and seek the right health professional at the right time. ^[1][4][5]

What is CRPS?

Complex regional pain syndrome is a neurological condition that causes pain in a specific region of the body (usually the hand, arm, foot, or leg) along with sensory, vascular (vasomotor), sweating/swelling (sudomotor/edema), and movement-related (motor/trophic) changes. Cleveland Clinic describes it as an "overreaction" or faulty response of the brain and nervous system to an injury; in other words, the nervous system keeps sending pain and inflammation signals that should normally settle down. ^[3][4]

CRPS has had several names in the past. The term reflex sympathetic dystrophy (RSD) was used for Type 1, while causalgia referred to Type 2, which is accompanied by an identifiable nerve injury. Today both are grouped under the umbrella term "complex regional pain syndrome." ^[4][5]

The key distinction between the two types is whether a demonstrable nerve injury is present:

• ·Type 1 (formerly RSD): Develops without a distinct, identifiable nerve injury. About 90% of cases are this type. ^[3]
• ·Type 2 (formerly causalgia): Develops after an identifiable peripheral nerve injury; the symptoms are largely similar to Type 1. ^[3][5]

An important point: CRPS is not a common condition, but it is not extremely rare either. A Dutch study reported an annual incidence of roughly 26 cases per 100,000 people, while an older U.S. study reported a rate of 5.46 cases per 100,000 person-years for Type 1. This difference between studies relates to variations in diagnostic criteria and methods. ^[5]

What are the symptoms?

The most defining feature of CRPS is pain that is out of proportion to the original injury, persistent, and often described as burning or throbbing. The pain usually starts in one region of an arm or leg and, in some people, may spread over time. Mayo Clinic and Cleveland Clinic list the following symptoms that may occur in CRPS: ^[1][3]

• ·Pain: Continuous burning, throbbing, or aching pain.
• ·Heightened sensitivity (allodynia and hyperalgesia): Even light touch, cold air, or the contact of clothing that would not normally hurt can be painful; a painful stimulus may be felt far more intensely than expected.
• ·Temperature and color changes (vasomotor): The affected area may appear warm and red at times, cold and pale/bluish at others. This can change over the course of a day.
• ·Swelling (edema): Noticeable swelling in the affected hand or foot.
• ·Sweating changes (sudomotor): Increased or decreased sweating in the area; marked asymmetry between the two sides.
• ·Movement and motor changes: Joint stiffness, reduced range of motion, weakness, tremor, and sometimes muscle contraction (dystonia).
• ·Trophic changes: Over time, changes in hair and nail growth, thinning or shiny skin, and muscle wasting.

Symptoms vary from person to person and over time. NINDS notes that in some people symptoms resolve on their own, while in others they can last for months or even years. In the early stage, pain, swelling, redness, and warmth often predominate; later, the limb may become cold and pale, with more pronounced skin and nail changes and muscle stiffness. ^[1][4]

Causes and risk factors

The cause of CRPS is not fully understood. The prevailing view is that it results from an abnormal response of the peripheral and central nervous systems following an injury; inflammation, dysregulation of the autonomic (sympathetic) nervous system, and sensitization of pain pathways all play a role. Mayo Clinic emphasizes that CRPS typically develops after an injury, surgery, stroke, or heart attack—yet the pain is out of proportion to the severity of the initial event. ^[1][4]

According to NINDS, more than 90% of cases have a clear history of trauma or injury. The most common triggers are: ^[4]

• ·Fractures (wrist / distal radius fractures are among the most frequently reported triggers),
• ·Sprains and strains,
• ·Soft tissue injuries (burns, cuts, bruises),
• ·Immobilization of the limb (for example, being in a cast),
• ·Surgical or medical procedures (including needlestick).

In terms of risk factors, CRPS occurs more often in women than in men. Epidemiological data report a markedly higher incidence in women compared with men, with an increased risk in the postmenopausal period. It can also occur in children and adolescents; however, this age group is generally reported to have a better outcome (prognosis). ^[4][5]

An important caveat: not everyone who has a fracture or sprain develops CRPS. The rate of CRPS after a fracture varies across studies but is low. Even so, pain that is far more severe and longer-lasting than expected after an injury is a warning sign that should be recognized and assessed early. ^[5]

How is it diagnosed? (the Budapest criteria)

There is no single blood test or imaging study that definitively diagnoses CRPS. The diagnosis is clinical; that is, the clinician evaluates the person's history and examination findings and rules out other conditions that can cause similar symptoms. The most widely used standard in this clinical assessment is a set of diagnostic criteria known as the "Budapest criteria." ^[2][5]

The Budapest criteria evaluate symptoms across four main categories: ^[5]

1. ·Sensory: Hyperalgesia (an exaggerated response to a painful stimulus) and/or allodynia (pain from a non-painful stimulus).
2. ·Vasomotor: Temperature asymmetry between the two sides and/or changes or asymmetry in skin color.
3. ·Sudomotor/edema: Swelling and/or changes or asymmetry in sweating.
4. ·Motor/trophic: Decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nail, skin).

The general principle for diagnosis is as follows: there must be no other diagnosis that better explains the findings, the person must report symptoms in at least three categories (described by the patient), and there must be signs in at least two categories on examination (observed by the clinician). These clinical criteria have high sensitivity. ^[5]

The clinician may order additional tests to support the diagnosis and rule out other conditions. The supportive investigations noted by Mayo Clinic and Cleveland Clinic include bone scans, sweat-production tests, X-rays, and MRI. These tests do not make a definitive diagnosis; they add clues to the picture or help exclude alternatives such as infection, vascular occlusion, or rheumatologic disease. ^[2][3]

Another critical point: in diagnosing CRPS, it is just as important to ensure that no neurological, musculoskeletal, or other medical condition better explains the symptoms as it is to meet the minimum criteria. For this reason, the diagnosis should be made by an experienced clinician. ^[5]

Treatment options (multidisciplinary)

There is no definitive cure for CRPS yet; however, with the right, early approach, symptoms can be controlled, function preserved, and—in some people—significant improvement and even remission achieved. Both Mayo Clinic and NINDS emphasize that treatment is much more effective when started early. ^[2][4]

The contemporary treatment approach is multidisciplinary and multimodal; that is, it relies not on a single method but on combining several approaches. The main components of treatment are: ^[2][6]

• ·Physical and occupational therapy (physiotherapy and OT): The cornerstone of treatment for preserving movement and regaining function. Discussed in detail below.
• ·Medication: Various drug classes targeting pain, inflammation, and neuropathic pain may be used. The choice of medication is entirely individualized and must always be arranged by a physician; this guide does not provide drug names or dosing recommendations.
• ·Psychological support: Chronic pain can lead to anxiety, depression, sleep problems, and avoidance of movement. Cognitive-behavioral approaches and pain-management education support the person's active participation in treatment. ^[6]
• ·Interventional methods: In some people, after physician assessment, advanced methods such as nerve blocks or neuromodulation (for example, spinal cord stimulation) may be considered. These are not suitable for every patient and require specialist judgment. ^[2]

The NHS likewise states that CRPS is managed not with a single method but with an approach that combines physical treatments, medicines, and psychological support. The goal of treatment is often not to eliminate pain entirely but to reduce pain, maintain movement, and preserve daily function and quality of life. ^[6]

How does physiotherapy help? (graded movement, mirror therapy)

Physiotherapy is central to CRPS management. This is because not using the limb due to pain (immobility) quickly creates a vicious cycle that leads to joint stiffness, muscle wasting, circulatory problems, and further reinforcement of pain. The fundamental aim of physiotherapy is to break this cycle and safely restore movement and function. ^[2][6]

The main physiotherapy approaches used in CRPS:

• ·Graded movement and exercise: Movements are increased gradually, step by step, in a way that keeps pain within manageable limits. The aim is not to protect the limb completely but to restore function through controlled and progressively increasing use. This approach helps avoid the trap of "not using it at all because of pain." ^[4][6]
• ·Graded motor imagery and mirror therapy: This is an advanced physiotherapy program aimed at reorganizing the brain's distorted perception of the affected limb. It consists of three stages: first left/right discrimination (laterality recognition), then mentally rehearsing movement (motor imagery), and finally mirror therapy. In mirror therapy, the reflection of the healthy limb in a mirror is perceived as the affected limb, retraining the brain through the illusion of "pain-free movement." A review reports that graded motor imagery and mirror therapy can produce meaningful improvements in pain and function in CRPS Type 1; however, because the studies have small sample sizes, the results should be interpreted with caution. ^[7]
• ·Desensitization: Used to reduce heightened sensitivity. As described by the NHS, materials of different textures (such as wool and silk) are first applied to a healthy area near the affected region; the same materials are then gradually applied to the affected area. It may be uncomfortable at first, but over time the area's tolerance to touch may improve. ^[6]
• ·Edema management, stretching, strengthening, and balance work: Controlling swelling, preserving joint range of motion, and regaining muscle strength and balance are other parts of the program.

Physiotherapy should always be individually planned and carried out under the supervision of a physiotherapist. Home-based rehabilitation programs can be valuable for breaking the cycle of immobility and sustaining a regular exercise habit. FizyoArt's home-based neurological rehabilitation and home-based orthopedic rehabilitation services allow such graded, supervised programs to be delivered in the person's own environment. The content of the program must always be determined together with the diagnosing physician and physiotherapist. ^[2][6]

What can be done at home; who is and is not a suitable candidate

What can be done at home in CRPS is a supportive part of the treatment plan and should be carried out with physician/physiotherapist approval. The NHS notes that teaching self-management strategies that enable a person to control their own condition is an important component of treatment. ^[6]

Approaches commonly recommended at home and generally considered safe:

• ·Following the graded exercise program given by your physiotherapist regularly and without interruption.
• ·Repeating desensitization exercises in the manner taught.
• ·Not leaving the limb completely immobile; continuing to use it in daily activities within pain limits.
• ·Activity pacing: Planning activity in a balanced way, breaking it up to avoid overexertion.
• ·Lifestyle measures that support sleep, stress, and general health.

Situations where self-directed home practice is not appropriate:

• ·Undiagnosed, unexplained severe pain: assessment is needed first.
• ·Performing aggressive, pain-provoking exercises without physician/physiotherapist supervision (this can worsen symptoms).
• ·Starting, stopping, or changing the dose of medications on your own.
• ·Situations where the "red flag" symptoms below are present (urgent assessment is needed).

In short, the home program should be an extension of a professional plan; following a program taken from the internet without guidance is not safe. To determine the most suitable approach for each person, it is essential to stay in communication with the diagnosing team. ^[4][6]

When to see a doctor (red flags)

CRPS has a much better course with early diagnosis and treatment, so recognizing warning signs is important. Mayo Clinic and NINDS emphasize that starting treatment early increases the chance of improvement and even remission. ^[2][4]

You should see a health professional in the following situations:

• ·Pain that is far more severe and persistent than expected after an injury, fracture, or surgery,
• ·Pain triggered by light touch, cold, or the contact of clothing (allodynia),
• ·Changes in color, temperature, sweating, or swelling in the affected area,
• ·Progressively increasing joint stiffness, loss of movement, or weakness.

Situations that may require more urgent assessment ("red flags") include:

• ·Signs of infection: Marked redness, warmth, drainage, bad odor, and fever.
• ·Suspected circulation problem: Sudden coldness, bluish discoloration, or pulse changes in the limb.
• ·Sudden, rapidly progressing loss of strength or loss of function.

Because these symptoms may also point to emergencies other than CRPS—such as infection, deep vein thrombosis, or vascular occlusion—medical help should be sought without delay. Waiting for the pain to "pass" without a personal assessment can cause loss of valuable time, both in CRPS and in these emergencies. ^[1][4]

Quick summary (TL;DR)

• ·CRPS is a chronic pain condition that usually affects an arm or leg, most often after an injury/fracture/surgery, with pain out of proportion to the original event. ^[1][4]
• ·There are two types: Type 1 (RSD, without nerve injury, ~90%) and Type 2 (causalgia, with an identified nerve injury). ^[3][5]
• ·Symptoms: burning pain, heightened sensitivity (allodynia), skin color/temperature/sweating changes, swelling, loss of movement, and trophic changes. ^[1][3]
• ·Diagnosis is clinical; the most common standard is the Budapest criteria. There is no single definitive test. ^[2][5]
• ·Treatment is multidisciplinary: physiotherapy/OT, medications, psychological support, and—in selected cases—interventional methods. There is no cure, but early treatment markedly improves outcomes. ^[2][4][6]
• ·The role of physiotherapy is central: graded movement, graded motor imagery, mirror therapy, and desensitization. ^[6][7]
• ·Seeking care early matters; infection, circulation problems, or sudden loss of function are red flags. ^[4]

Frequently Asked Questions

Are CRPS and RSD the same thing?

Largely, yes. Reflex sympathetic dystrophy (RSD) was the older name used for what is now called CRPS Type 1, and causalgia was the term for Type 2 (with an identified nerve injury). Today both are grouped under the umbrella term "complex regional pain syndrome." ^[4][5]

Does CRPS go away or get better?

There is no definitive cure for CRPS yet. However, according to NINDS, in some people symptoms can resolve on their own; with early and appropriate treatment, significant improvement and even remission are possible. In other people, symptoms may last for months or years. The course varies from person to person, and early treatment is an important advantage. ^[2][4]

Can CRPS be diagnosed with a single test?

No. There is no single test that definitively diagnoses CRPS. The diagnosis is made clinically, most often using the Budapest criteria and by ruling out other conditions. X-rays, MRI, bone scans, and sweat-production tests may help but cannot make the diagnosis on their own. ^[2][3][5]

Does physiotherapy increase CRPS pain?

A well-planned, graded physiotherapy program is generally safe and aims to improve pain and function over the long term. Exercises may cause some discomfort at first, which is why the program is progressed under a physiotherapist's supervision in a way that keeps pain within manageable limits. Unsupervised, overly demanding exercises can worsen symptoms. ^[6][7]

What is mirror therapy, and how does it help?

Mirror therapy is one stage of a graded motor imagery program. The reflection of the healthy limb in a mirror is perceived as the affected limb, retraining the brain through the illusion of "pain-free movement" and aiming to correct the distorted perception of the affected limb. Studies report benefits for pain and function in CRPS Type 1; however, it is recommended that it be carried out under the guidance of a physiotherapist. ^[7]

Why is CRPS more common in women?

Epidemiological data show that CRPS occurs more often in women than in men and that the risk increases in the postmenopausal period. The underlying mechanisms are not fully known, but hormonal and nervous-system-related factors may play a role. ^[5]

Does everyone develop CRPS after a fracture?

No. Although fractures and sprains are among the most common triggers of CRPS, the vast majority of people who have an injury do not develop it. However, pain that is far more severe and longer-lasting than expected after an injury is a warning sign that should be assessed early. ^[4][5]

What can I do for CRPS at home?

Following the graded exercise and desensitization program given by your physiotherapist regularly, continuing to use the limb within pain limits, and planning activity in a balanced way (pacing) are generally recommended. However, the home program should be an extension of a professional plan; starting/stopping medications on your own or doing unsupervised excessive exercise is not safe. If red-flag symptoms appear, be sure to seek medical care. ^[4][6]

This content is for informational purposes and is not a substitute for a personal medical assessment. Anyone who suspects CRPS or has new or worsening symptoms should consult a health professional. ^{[1][2][4][5][6]}