Also called: CRPS · Causalgia · Reflex sympathetic dystrophy
Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Complex Regional Pain Syndrome
Complex regional pain syndrome (CRPS) is a chronic pain condition. It causes intense pain, usually in the arms, hands, legs, or feet. It may happen after an injury, either to a nerve or to tissue in the affected area. Rest and time may only make it worse.
Symptoms in the affected area are:
- Dramatic changes in skin temperature, color, or texture
- Intense burning pain
- Extreme skin sensitivity
- Swelling and stiffness in affected joints
- Decreased ability to move the affected body part
The cause of CRPS is unknown. There is no specific diagnostic test. Your doctor will diagnose CRPS based on your signs and symptoms.
There is no cure. It can get worse over time, and may spread to other parts of the body. Occasionally the symptoms go away, either temporarily or for good. Treatment focuses on relieving the pain, and can include medicines, physical therapy, and nerve blocks.
It sits within Brain and Nerves.
The lead U.S. institute for this subject is the National Institute of Neurological Disorders and Stroke.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Complex Regional Pain Syndrome
232 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- Transcutaneous Auricular Vagus Nerve Stimulation Added to Rehabilitation for Complex Regional Pain Syndrome Type ILiv Hospital Vadistanbul
- Evaluation of IV AMBTX-01 (Neridronate) for Treatment of CRPS Type 1 (CRPS-RISE)Ambros Therapeutics, Inc.
- TMS for Complex Regional Pain SyndromeStanford University
- Dance-therapy and Chronic PainHospices Civils de Lyon
- Effectiveness of Transcranial Direct Current Stimulation (tDCS) in the Management of Complex Regional Pain SyndromePolyclinique de l'Europe
- Low Dose Naltrexone Therapy for Complex Regional Pain SyndromeHospital for Special Surgery, New York
Research already completed
- Empowered Relief for YouthStanford University
- Interest of Day Hospital Care for Patients With Chronic Regional Pain Syndrome Referred to the Chronic Pain Unit for the First TimeCentre Hospitalier le Mans
- Contribution of Immersive Virtual Reality to a Standardized Rehabilitation Program for Upper Limb Chronic Pain: A Single-Case Experimental Design StudyUniversity Hospital, Angers
- Role of Vitamin C at 6 Months on Incidence of Complex Regional Pain Syndrome Type I in Upper Limb SurgeryCentre Hospitalier Universitaire, Amiens
- Evaluation of the Relationship Between the Duration of the Evolution of the Complex Regional Pain Syndrome Type 1 (CRPS 1) and Effectiveness of the Continuous Peripheral Nerve Block (CPNB) Associated With an Intensive Rehabilitation ProgramPôle Saint Hélier
- Effects of Motor Imagery Technique With and Without Virtual Reality on Pain Intensity ,Functional Disability and Quality of Life in Patient With Post Stroke Shoulder Hand SyndromeGreen International University
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Learn More
- Complex Regional Pain SyndromeNational Institute of Neurological Disorders and Stroke
- Complex Regional Pain SyndromeMayo Foundation for Medical Education and Research
- Complex Regional Pain Syndrome (Reflex Sympathetic Dystrophy)American Academy of Orthopaedic Surgeons
- Signs and Symptoms of CRPS/RSDReflex Sympathetic Dystrophy Syndrome Association of America
Clinical Trials
- ClinicalTrials.gov: Complex Regional Pain SyndromesNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Complex Regional Pain Syndromes. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Complex Regional Pain Syndrome, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.