Complex Regional Pain Syndrome: Diagnosis, Pathophysiology, and Treatment Approaches.

Journal and index pages often block iframe embedding. This reader keeps the evidence details in Orthonotes and leaves the source page one click away.

Abstract

Conflict of interest statement: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work. 2. Complex Regional Pain Syndrome. Guthmiller KB(1), Dua A(2), Dey S(3), Varacallo MA(4). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan–. 2025 May 4. Author information: (1)USC Keck School of Medicine (2)Augusta University (3)Geisel School of Medicine at Dartmouth/ Dartmouth-Hitchcock Medical Center (4)Penn Highlands Healthcare System Complex regional pain syndrome (CRPS) is a neuropathic pain disorder characterized by persistent pain that is disproportionate to the severity of the tissue injury and continues beyond the usual expected period of tissue healing. The pain is accompanied by sensory, motor, and autonomic abnormalities. Such abnormalities include allodynia, hyperalgesia, sudomotor and vasomotor abnormalities, and trophic changes. The pain is regional and does not follow a specific dermatome or myotome pattern. This disabling condition often develops after a trauma, fracture, or surgery. Some spontaneous cases have also been reported. In the 16th century, Ambroise Paré first reported cases with symptoms similar to CRPS, which developed after phlebotomy. In 1864, Silas Mitchell observed this syndrome after gunshot wounds. He used the term causalgia to describe this syndrome in 1872. James A. Evans coined the term reflex sympathetic dystrophy in 1946 to describe a similar condition, in which he suspected that sympathetically mediated pain was involved. Finally, in 1994, the International Association for the Study of Pain (IASP) named this condition complex regional pain syndrome and proposed diagnostic criteria. Due to low specificity, a widely accepted revised set of criteria was proposed in 2010 and is commonly referred to as the Budapest Criteria. CRPS is classified into 2 subtypes—type 1, previously referred to as reflex sympathetic dystrophy, and type 2, formerly called causalgia. Type 1 arises without nerve trauma, whereas type 2 follows a known nerve injury. These conditions present with indistinguishable clinical features, typically affecting a regional area rather than following a dermatomal or peripheral nerve distribution. Symptoms typically involve the distal extremities but may extend proximally or to the contralateral limb. CRPS can also be categorized as warm or cold and may be sympathetically maintained or independent—classifications that influence prognosis and treatment strategies. In addition to impairing function, sleep, and activities of daily living, CRPS imposes a substantial psychological and psychosocial burden. The condition's variable clinical spectrum and poorly defined pathophysiology complicate management. Copyright © 2026, StatPearls Publishing LLC.