RARE DISEASERESEARCH ATLAS
Open navigation menu

ORPHA:83452

Complex regional pain syndrome

low confidenceDisorder

Also known as: Sudeck's atrophy · Causalgia · Reflex sympathetic dystrophy · Algodystrophy · Algoneurodystrophy

Publications

18,752

Trials

157

Interventional, condition-specific

Researchers

976

Distinct authors in sample

Gene link

—

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare neurologic disease characterized by persistent pain that is disproportionate to the inciting event. The pain is regional, usually affecting a limb with a distal predominance, and may occur spontaneously or be stimulus-induced. It is associated with sensory disturbances, vasomotor abnormalities (including changes in skin color and temperature), sudomotor abnormalities, edema, and motor or trophic changes. Symptoms often develop following trauma, fractures, immobilization, surgery, or nerve injury, and their severity and clinical presentation can vary considerably among patients.

How rare: How common this is has not been clearly measured.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (2)

CRPS · algoneurodystrophy

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

4/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    18,752 matched papers (8,880 in last 10 years) Source

  3. Phenotype characterisedPresent

    12 HPO annotations (e.g. Dry skin; Somatic sensory dysfunction; Slow-growing nails) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationPresent

    5 FDA · 5 EMA designations (5 FDA orphan-indication approvals) — e.g. ketamine Source

  6. Interventional trialPresent

    157 matched on ClinicalTrials.gov (27 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

12

Associated phenotypes · MONDO:0019369

  • Dry skin
  • Somatic sensory dysfunction
  • Slow-growing nails
  • Erythema
  • Abnormality of hair growth

Showing 5 of 12 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

10

Designations · 5 with FDA orphan-indication approval

  • FDA ketamineComplex regional pain syndrome · 2019-02-01 · Not FDA Approved for Orphan Indication
  • FDA delta-9-tetrahydrocannabinol and cannabidiolComplex regional pain syndrome · 2018-03-07 · Not FDA Approved for Orphan Indication
  • FDA baclofenComplex regional pain syndrome · 2015-10-28 · Not FDA Approved for Orphan Indication
  • FDA zoledronic acidComplex regional pain syndrome · 2013-05-06 · Not FDA Approved for Orphan Indication
  • FDA neridronateComplex regional pain syndrome · 2013-03-25 · Not FDA Approved for Orphan Indication
  • EMA afatinibTreatment of complex regional pain syndrome · 28/06/2024 · PositiveEMA designation
  • EMA cannabidiol;DronabinolTreatment of complex regional pain syndrome · 12/11/2021 · PositiveEMA designation
  • EMA zoledronic acidTreatment of complex regional pain syndrome · 07/10/2013 · PositiveEMA designation

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

30

Drugs / clinical candidates · MONDO_0019369

CTD chemicals (MyDisease.info)

3 associated chemicals. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Ascorbic Acid · therapeutic
  • Bretylium Compounds · therapeutic
  • Morphine · therapeutic

MyDisease.info · MONDO:0019369

Literature

Is anyone studying this?

18,752

18,752 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

18,752 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

8,880 in the last 10 years · low confidence

Phrase hits: 18,736 · MeSH hits: 99

Open Europe PMC search

Who's working on it?

976

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Wang Y5 papers · 2026

    Department of Foot and Ankle Surgery, The Second Qilu Hospital of Shandong University, 250033, Jinan, China.

    Papers in Europe PMC
  2. 02
    Chang MC4 papers · 2025

    Department of Rehabilitation Medicine, College of Medicine, Yeungnam University, Daegu, Korea.

    Papers in Europe PMC
  3. 03
    Ferraro MC4 papers · 2026

    Centre for Pain IMPACT, Neuroscience Research Australia, Sydney, Australia.

    Papers in Europe PMC
  4. 04
    Rosini S4 papers · 2026

    Biomaterial Research Center, 57121 Livorno, Italy.

    Papers in Europe PMC
  5. 05
    Adami G3 papers · 2025

    Rheumatology Unit, University of Verona, Italy. giovanni.adami@univr.it.

    Papers in Europe PMC
  6. 06
    Benini C3 papers · 2025

    Rheumatology Unit, University of Verona, Italy.

    Papers in Europe PMC
  7. 07
    Bruehl S3 papers · 2026

    Vanderbilt University Medical Center, Nashville, TN, United States.

    Papers in Europe PMC
  8. 08
    Brunner F3 papers · 2026

    Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.

    Papers in Europe PMC
  9. 09
    Ciaffi J3 papers · 2026

    Medicine & Rheumatology Unit, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.

    Papers in Europe PMC
  10. 10
    Drummond PD3 papers · 2026

    School of Psychology and Centre for Healthy Ageing, College of Health and Education, Murdoch University, Murdoch WA, Australia.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

157

interventional trials for this specific condition

157 interventional trials matched this specific condition name; 27 currently recruiting in our sample.

Data as of 11 September 2026

157 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 99.1th percentile).

low confidence · 99.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

157 interventional trials matched after quoted-phrase search and title/condition post-filter.

Observational and natural-history studies

47 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 45 · after dedupe 45 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 45 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Uncertain / not reviewed (45)

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Complex regional pain syndrome — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"Complex regional pain syndrome" OR "Sudeck's atrophy" OR "Causalgia" OR "Reflex sympathetic dystrophy" OR "Algodystrophy" OR "Algoneurodystrophy"

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Complex Regional Pain Syndromes

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Complex regional pain syndrome" OR "Sudeck's atrophy" OR "Causalgia" OR "Reflex sympathetic dystrophy" OR "Algodystrophy" OR "Algoneurodystrophy" OR "Complex Regional Pain Syndromes"

Interventional trials matched via: both, phrase, mesh (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 157 interventional · 47 observational · 1 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase, mesh; with hits: phrase, mesh

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: CRPS

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (18752) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-27T02:36:05.855Z