Complex Regional Pain Syndrome (CRPS)
formerly Reflex Sympathetic Dystrophy (RSD)

Hyperbaric Oxygen Therapy Approval Status

No Clearance by US Food and Drug Administration (FDA)

No Approval by the Undersea and Hyperbaric Medical Society (UHMS)

! Read the US Food and Drug Administration (FDA) position paper on off-label hyperbaric treatment:
Hyperbaric Oxygen Therapy: Don't Be Misled, published 22 August 2013.

About Clearance and Approval


Definition and Causes

Complex regional pain syndrome is a chronic, progressive pain disorder. Severe burning or shooting electrical pain typically begins in one arm, hand, leg, or foot then spreads to other limbs and the whole body. People with advanced CRPS often experience dramatic changes in skin color, temperature, sensitivity, and tenderness accompanied by sweating and swelling.

Complex regional pain syndrome has no known cause. Researchers have observed abnormalities in sympathetic nerve, immune response, and inflammation pathways. Many patients attribute the onset of CRPS to a particular injury. There are two types of CRPS: Type I or reflex sympathetic dystrophy (RSD) and Type II or causalgia, in which there is evidence of nerve damage.

Evidence Index

FDA cleared, widely reimbursed
Strong body of evidence
Repeatedly favorable results
Early or mixed results
Unfavorable or no evidence
Strong evidence against HBOT

Treatment with Hyperbaric Oxygen Therapy

In limited studies hyperbaric oxygen therapy (HBOT) has been shown to reduce the pain and tenderness associated with complex regional pain syndrome (CRPS) and other chronic pain disorders. Physicians may prescribe HBOT as an adjunct or alternative to drug treatments and other therapies.

HyperbaricLink Commentary

Although there have been controlled, double-blinded studies of treatment of complex regional pain syndrome with hyperbaric oxygen, much of this research was conducted outside the United States or was limited to animal models. As of July 2015 there are no studies of CRPS and HBOT registed on [ ] With such limited supporting data and no future research planned, we rate the amount of available supporting evidence for the effective treatment of CRPS with HBOT as scant.

Those seeking treatment for chronic regional pain syndrome should beware of practitioners making bold claims for hyperbaric oxygen therapy. Advertising a specific medical benefit from a treatment that has not been approved by the US Food and Drug Administration for that purpose is a violation of US federal law. Never pay to participate in a clinical trial.

Patient Resources

HyperbaricLink recommends the following websites for anyone seeking authoritative information, patient advocacy, and community support for complex regional pain syndrome.

Complex Regional Pain Syndrome Fact Sheet
US National Institute of Neurological Disorders and Stroke (NINDS)
US National Institutes of Health (NIH)

The NIH fact sheet on CRPS contains comprehensive information about symptoms, diagnosis, potential causes, and treatment of chronic regional pain syndrome.

Wikipedia: Complex regional pain syndrome

The Wikipedia entry on CRPS/RSD provides a good overview of the condition and current treatments. With extensive footnotes, the page is a good jumping-off point for those who would like a deep dive into some of the relevant published research.

HyperbaricLink Commentary

Patients and their caregivers should use caution and a healthy dose of scepticism when evaluating the claims for hyperbaric oxygen therapy made on the websites of some organizations involved with the CRPS/RSD patient community. Much of the anecdotal evidence presented in these claims comes from a very small group of HBOT pratitioners who have made a business of off-label treatment of CRPS/RSD. As noted in our Evidence Index and our commentary in the Treatment section, our assessment of the available clinical research is that these claims are not supported by the scientific evidence.

US Food and Drug Administration (FDA) rules about advertising off-label treatment exist to protect the public. See our section on Clearance and Approval for more information about how a treatment is determined to be safe and effective for a medical condition.

Clinical Resources

Start with the following resources to explore current research activities and the peer-reviewed medical literature on hyperbaric oxygen therapy for complex regional pain syndrome.

 Use the search buttons below to go directly to research on hyperbaric oxygen therapy.
US National Institutes of Health keeps the official list of human clinical trials currently enrolling, in progress, and recently completed. One may reasonably question the size and legitimacy of any study not listed here.



HBOEvidence uses computerized tools to appraise the key randomized controlled trials (RCTs) in the hyperbaric medical literature. One may reasonably question the overall strength of HBOT evidence for any disease or condition not covered here.

Search HBOEvidence
US National Library of Medicine, US National Institutes of Health

PubMed keeps the official list of scientific papers published in reputable peer-reviewed medical journals. One may reasonably question the importance and legitimacy of any study not listed here.



News About CRPS and Hyperbaric Oxygen Therapy

More news from O2.0 – the HyperbaricLink blog

Complete complex regional pain syndrome news archive from O2.0 — the HyperbaricLink blog.

Reflex Sympathetic Distrophy,US National Institute of Neurological Disorders and Stroke. Retrieved 10 May 2011.
Complex Regional Pain Syndrome, Mayo Clinic Proceedings. Retrieved 02 May 2015.
Page Data
Updated: 04 Aug 2015 12:33 PM
Created: 29 Nov 2009 12:00 AM
By: About the authors »