SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyDrug Reaction DataReferences

View all Images (2)

Complex regional pain syndrome
Other Resources UpToDate PubMed

Complex regional pain syndrome

Contributors: Andrea Wasilewski MD, Richard L. Barbano MD, PhD
Other Resources UpToDate PubMed


Complex regional pain syndrome (CRPS) comprises two subtypes, depending on whether or not primary nerve injury is the main provocative component. Complex regional pain syndrome (CRPS) type 1, also known as reflex sympathetic dystrophy, is an uncommon syndrome of unknown etiology. It is characterized by symptoms of spontaneous and evoked neuropathic pain, with varied qualities such as burning, stabbing, and throbbing, as well as pain in response to nonpainful stimuli (allodynia) and pain out of proportion to stimulus (hyperalgesia). It is almost always accompanied by at least one of the following: tenderness, swelling, changes in skin color and temperature of a body part / extremity, abnormal sudomotor activity, limb hair changes, atrophy, or focal osteoporosis. There is a close association with sympathetic abnormalities, and this is often referred to as sympathetically maintained pain (SMP). There is usually a history of prior injury or surgery. CRPS type 1 is without clear nerve injury.

CRPS type 2, formerly called causalgia, has similar symptoms but with peripheral nerve injury as a major part of initiating the syndrome.


G56.40 – Causalgia of unspecified upper limb
G57.70 – Causalgia of unspecified lower limb
G90.50 – Complex regional pain syndrome I, unspecified

128200000 – Complex regional pain syndrome

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

  • Neuropathy
  • Nerve injury
  • Ischemia
  • Lymphedema
  • Postherpetic neuralgia
  • Thalamic pain syndrome
  • Erythromelalgia
  • Acute compartment syndrome
  • Peripheral arterial disease
  • Raynaud phenomenon
  • Deep vein thrombosis

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required

Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

Subscription Required


Subscription Required

Last Reviewed:08/07/2018
Last Updated:09/05/2018
Copyright © 2024 VisualDx®. All rights reserved.
Complex regional pain syndrome
A medical illustration showing key findings of Complex regional pain syndrome : Dystonia, Joint stiffness, Muscle atrophy, Hyperhidrosis, Limb pain, Tremor
Copyright © 2024 VisualDx®. All rights reserved.