Complex regional pain syndrome (CRPS): Information and specialists for CRPS


Complex regional pain syndrome (CRPS), also known as Sudeck's atrophy after the first person to describe it, is defined by physicians as persistent and severe pain, usually in the leg or arm, often accompanied by limited mobility of the affected limb. Learn more about the cause, symptoms, therapy and treatment options, prognosis, and self-help options here.

Here you can find additional information and highly qualified specialists and centers for the treatment of complex regional pain syndrome.

ICD codes for this diseases: G90.5, G90.6

Selected specialists for CRPS

Brief overview:

  • What is complex regional pain syndrome? Also called CRPS and Sudeck's atrophy, it is a form of chronic pain, primarily pain on being touched, associated with inflammation.
  • Causes: The causes are still not fully understood. Inflammatory and neurogenic processes in combination with changes in the central nervous system appear to cause the disease.
  • Symptoms: The symptoms that occur can vary as the disease progresses. Typical symptoms are pain, swelling, changes in skin color and temperature, sweating, and changes in fingernail and hair growth.
  • Diagnosis: The disease is diagnosed by ruling out other conditions. The use of imaging techniques is not necessary. Instead, there are a number of criteria to be clarified.
  • Treatment: The therapy depends on the symptoms that occur. Multimodal pain management is recommended; treating the inflammation is also one of the most important treatment goals. Psychotherapy is also very important to help sufferers learn how to cope with their condition.
  • Prognosis: The earlier the disease is detected, the better the prognosis. However, good progress is still possible later on.

Article overview

Definition: What is CRPS (Sudeck's atrophy)?

Complex regional pain syndrome, or CRPS for short, is also known as "Sudeck's disease" or "reflex sympathetic dystrophy." It manifests in the form of (constant) pain, mainly due to

  • Pain on being touched (allodynia),
  • Inflammation,
  • Reduced mobility and reduced strength, and
  • Sensitivity disorders.

The disease mainly affects the patient’s hands or feet.

CRPS occurs after arms or leg injuries at a frequency of 2-15%. This risk exists especially after

Occurrence after minor injuries, such as after cuts or insect bites, is less common.

Women are affected two to three times more often than men. CRPS occurs primarily between the ages of 40 and 70, and it rarely occurs in childhood or old age.

Causes of CRPS

The cause of CRPS is not fully understood to date. There is a suspicion that it is a combination of

  • Inflammatory and neurogenic (stemming from nerve) processes and
  • Changes in the area of the brain and spinal cord.

These various processes are responsible for the wide range of symptoms. However, not every symptom occurs in everyone.

Endogenous inflammation is normal. It always occurs after tissue damage and is regulated by the body. In CRPS, however, this inflammatory response is more pronounced. The body can no longer control it.

However, a healing response may still begin months or years later.

A distinction is made between CRPS I and CRPS II. In CRPS I, there is no detectable nerve lesion. In CRPS II, there is damage to the nerves involved. However, this distinction is irrelevant for treatment. The therapies are identical.

Symptoms of CRPS

The symptomatology may change over the progression of the disease. Thus, central changes (spinal cord and brain) may occur later in the course of the disease.

The acute phase of the disease is characterized by excessive and prolonged inflammation. It usually lasts up to six months after the injury.

The visible symptoms include

  • Swelling,
  • Changes in skin color and temperature (warmer, colder) of the affected body part,
  • Increased sweating, and
  • Changes in fingernail and hair growth.

Other symptoms include impaired mobility, e.g.,

  • The fist cannot be completely closed or
  • The flexion and extension in the hand and ankle joint is reduced.

Strength is often diminished.

The pain present may be permanent or load-dependent. The severity of the pain may vary throughout the day. There may also be increases in pain due to external factors such as

  • Heat,
  • Cold, or
  • Light touch.

However, touch can also feel numb or tingle like pins and needles. Some patients feel that the affected body part no longer belongs to their body. This can result in new injuries, for example due to bumping.

crps schmerzsyndrom hand
Symptoms of CRPS in a hand © CRPS Network, courtesy of Ms. M. Burk.

Diagnostic evaluation for CRPS

The diagnosis of Sudeck's atrophy is made clinically. Imaging techniques such as X-rays, MRIs, and bone scintigraphies are not necessary. The doctor diagnoses CRPS based on specific symptoms and by ruling out other conditions.

The most important tool for diagnosis is the Budapest criteria, which can be found in the CRPS guideline.

Budapest Criteria

A persistent, excessive pain that can no longer be explained by the original injury.

The affected person must have at least one disease sign each from three of the following four categories:

  1. Hypersensitivity to pain stimuli (hyperalgesia) or to touch (hyperesthesia); normally non-painful touch produces pain, e.g., when touched gently (allodynia).
  2. In a side-by-side comparison (asymmetry), the skin temperature or skin color is changed (pale, bluish, reddened).
  3. In a side-by-side comparison, there is altered sweating or swelling due to increased stored tissue fluid (edema).
  4. Reduction in mobility due to, e.g., persistent change in involuntary muscle tension (dystonia), involuntary rhythmic trembling (tremor), or muscle weakness (paresis). Changes in hair or nail growth.

The affected person must have at least one sign of each of two of the following four categories present at the time of the medical examination:

  1. Triggering pain in the presence of an otherwise non-painful stimulus by, e.g., gently brushing the skin (allodynia) or hypersensitivity to, e.g., moderate, sharp stimuli such as touching with a toothpick. Pain when pressure is exerted on joints, bones, or muscles (hyperesthesia or hyperalgesia).
  2. Changed skin temperature or skin color in a side-by-side comparison.
  3. In a side-by-side comparison, altered local sweating or swelling due to an increase in stored tissue fluid (edema). 
  4. Reduction in mobility, due to, e.g., persistent change in involuntary muscle tension (dystonia), involuntary rhythmic trembling (tremor), or muscle weakness (paresis). Changes in hair or nail growth.
  1. There is no other diagnosis that fits the symptoms. Rheumatic disorders, thromboses, compartment syndrome, etc., must be excluded from the differential diagnosis. 

crps schmerzsyndrom fuss
Symptoms of CRPS in a foot © CRPS Network, courtesy of Ms. M. Burk.

Treatment options

A cause-related (causal) therapy for CRPS does not exist because the cause is unknown. Therapy is therefore based on the presenting symptoms as well as the CRPS guidelines. Multimodal pain management is recommended.

In this regard, pain therapists work with experts from occupational, physical, and psychotherapy. 

In the acute phase, anti-inflammatory therapy is important. Here, cortisone is predominantly used as long as inflammatory symptoms are still present. This treatment should not be performed for longer than a maximum of 6-12 months. 

The pain management usually consists of the temporary administration of

  • Anti-inflammatory painkillers and
  • Co-analgesics.

These include, for example, medication against

  • Epileptic seizures (so-called anticonvulsants) and
  • Depression (so-called antidepressants), which can also have a pain-relieving effect.

Surgery should be performed only in specialized centers when other therapies are insufficiently effective. In CRPS, surgical interventions of any kind, unless life-threatening, should be critically considered. They can cause a new onset of the disease in another extremity. 

One of the most important components of therapy is active physical and occupational therapy. Complete immobilization should be avoided. Exercises to improve strength and flexibility should also be performed at home.

Active exercises can lead to a temporary increase in pain. In the long term, they are important for maintaining function. 

Mirror therapy represents one therapeutic measure. In CRPS, areas of the brain that supply the diseased limb diminish in size. The body map is lost in the process. In mirror therapy, painless movement of the affected limb is simulated to the brain. This stimulates the neglected brain region.

Measures like

  • Ointments,
  • Elevation,
  • Heat or cold treatments such as cold packs, cherry pit pillows, or hay bags

can also provide relief.

Psychotherapeutic pain treatment of CRPS

Sudeck's atrophy is an extremely distressing pain disorder. That is why supportive psychotherapy is always advisable. It helps the person to cope better with life changes.

Certain psychological stresses ("stressful life events") can negatively influence the course of the disease. This is also true for other chronic pain diseases. However, they are never the cause of CRPS.

CRPS is a pain disorder that is accompanied by significant emotional consequences for many sufferers. Some sufferers show excessive anxiety and protective behavior. Others try to hide the disease and not let anything show.

Already in the first months of the disease, affected persons notice a strong physical and mental exhaustion. They often complain of

  • Sleep disorders,
  • Lack of drive,
  • Self-doubt, and
  • Especially fears about the future.

Psychological symptoms are thought to be the consequence and not the cause of CRPS.

Psychotherapeutic treatment is divided into several phases.

First phase of the psychotherapeutic treatment

In the first phase, the most important goal is education about the clinical picture tailored to the person affected. Psychotherapy also has the task of absorbing fear, anger, and helplessness because of the sudden physical and psychological changes.

Affected persons are restricted in almost all activities of daily life from one day to the next. This applies not only to professional and social activities, but also to everyday tasks such as

  • Washing,
  • Getting dressed,
  • Eating, and
  • Driving.

At the same time, the social environment often shows little understanding for the limitations of those affected. This usually causes them to withdraw socially.

For psychological stabilization, the following have proven to be particularly effective

  • Relaxation and imagination techniques (imagining positive images) and
  • The resumption of pleasant activities.

Medical, physiotherapeutic, and psychotherapeutic measures should always be coordinated. They are usually combined in multimodal pain management.

Second phase of psychotherapeutic treatment

In the second phase, techniques should be taught to help those affected,

  • Perceive their physical resilience and
  • Acquire appropriate physical relieving and loading behaviors.

Third phase of psychotherapeutic treatment

In the third phase of treatment, the person learns,

  • To have patience and perseverance,
  • To overcome resignation and phases of treatment standstill, and
  • To draw attention to (small) increments of progress again and again.

Furthermore, the therapist works out realistic plans for professional and private reintegration with the person concerned. These concerns should also be voiced in psychotherapy so that competent contacts can be arranged.

The "CRPS Network Strong Together" is an association of all CRPS self-help groups in Germany, Luxembourg, Switzerland, and Austria. Information on the disease, treatment options, and specialists are provided by the organization.

In addition, regional groups offer an exchange via the Internet and at regular meetings.


CRPS is a long-lasting condition and requires a lot of patience. In rare cases, chronic CRPS can progress to

  • The inability to use the affected body part and
  • A severe disability.

In general, the earlier the disease is detected and treated, the better the prognosis. But even after a longer period of illness, progress is possible. 

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