Editor’s Note: Celeste and I recently lost a friend who struggled with CRPS; she was a tireless advocate for all those who live with pain, and she is sorely missed.
Fibromyalgia (FM) and complex regional pain syndrome (CRPS) share something in common—neuroinflammation. A review of the literature in 2015, Neurogenic neuroinflammation in fibromyalgia and complex regional pain syndrome , says there are differing degrees to which neurogenic neuroinflammation might contribute to the multifactorial path of disease origin of both CRPS and FM. Another study in 2017  suggests a possible association between FM and the development of CRPS after distal radius fracture. Researchers concluded:
“While the basis of the association between fibromyalgia and CRPS is unknown, our data suggest that it could serve as a useful predictor of CRPS risk, promoting increased vigilance for CRPS symptoms and earlier recognition and treatment, thereby improving patient outcomes.”
What do CRPS and FM share?
Dr. Geoffrey Littlejohn says  they share:
- neuroinflammation — “Inflammatory features of CRPS are especially prominent early in the disease course, particularly the first six months. By contrast, in fibromyalgia, inflammation-related symptoms tend to fluctuate over long periods of time.”
- neurogenic inflammation — evidenced by skin color changes, tissue swelling, and temperature intolerances that are important in the early stages of both CRPS and fibromyalgia and can persist over time and contribute to ongoing key symptoms in each disorder.
- allodynia — an abnormal pain response to stimulation that ordinarily should not cause pain.
Side note: According to a Rheumatology Advisor article, The Role of Neurogenic Inflammation in Fibromyalgia Pathophysiology , neurogenic inflammation has been implicated in the pathophysiology of numerous diseases, including fibromyalgia, complex regional pain syndrome, migraine, and irritable bowel and bladder syndromes.
CRPS is a very painful chronic condition characterized by severe burning, abnormal changes in bone and skin, local excessive sweating, tissue swelling, and extreme sensitivity to touch. According to the National Institute of Neurological Disorders and Stroke Fact Sheet , diagnosis is based on a person’s medical history and signs and symptoms that match the definition and may be more difficult to diagnose later in the course of the disorder.
Fibromyalgia is characterized by abnormal body-wide chronic pain and tenderness, cognitive problems, fatigue, and often, disordered sleep. Additional symptoms and disorders may accompany fibromyalgia .
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Symptoms – compare and contrast
Many symptoms of CRPS and FM are similar and they can mimic other health disorders, but the defining feature between the two is that the pain of CRPS is concentrated in the injured/physically damaged area, while fibromyalgia pain and/or tenderness is body-wide. Shared symptoms are marked (*).
- Develops after physical trauma, infection, a blood vessel problem, or entrapment of the nerves and occurs in stages.
- Burning or throbbing pain usually involves one extremity, but it can advance to more than one limb.
- Touch or cold intolerance, particularly the affected limb.
- Swelling of the painful area and joint/s.
- Joint stiffness.*
- Skin – texture abnormalities and/or unusual sweating of the involved extremity.
- Livedo reticularis .*
- Raynaud’s . *
- Slow or rapid hair and nail growth.*
- Muscle spasms and weakness.*
- Decreased function of the extremity.
- Tissue wasting (atrophy).
- Muscle tightening (contracture) of affected area.
- Loss of proprioception (the sense of where our body is in the surrounding space).*
- Develops after physical trauma, infection, or significant psychological stress. Symptoms may gradually accumulate over time.
- Chronic body-wide pain usually described as dull and/or tender.
- Generalized hyper-sensitivity to touch or cold.
- Soft tissue swelling or fluid retention.
- Joint stiffness, particularly if myofascial pain syndrome , MPS, accompanies FM. *
- Skin – dry or unusual rashes.
- Livedo reticularis.*
- Raynaud’s .*
- Slow or rapid hair and nail growth.*
- Muscle spasms and weakness if MPS accompanies FM.*
- Decreased mobility and function when MPS accompanies FM.
- Poor tissue healing.
- Muscle tightening, particularly if myofascial pain syndrome accompanies FM.*
- Loss of proprioception (where we sense our body is in relationship to the environment).*
While complex regional pain syndrome and fibromyalgia share many symptoms – and both may be present – the conditions are different.
While there are similarities between CRPS and fibromyalgia, there are also vast differences. That said, with a focus on neuroinflammation and its role in both disorders, there could be some good news as Dr. LittleJohn tells Rheumatology Advisor  author, Cindy Lampner, “there has been recent approval of a monoclonal antibody to the pro-inflammatory calcitonin gene-related peptide for use in migraine, a condition also characterized by neuroinflammation.”
This article was first published on ProHealth.com on November 7, 2018 and was updated on June 7, 2021.
Celeste Cooper, RN, is a frequent contributor to ProHealth. She is an advocate, writer and published author, and a person living with chronic pain. Celeste is lead author of Integrative Therapies for Fibromyalgia, Chronic Fatigue Syndrome, and Myofascial Pain and Broken Body, Wounded Spirit, and Balancing the See Saw of Chronic Pain (a four-book series). She spends her time enjoying her family and the rewards she receives from interacting with nature through her writing and photography. You can learn more about Celeste’s writing, advocacy work, helpful tips, and social network connections at CelesteCooper.com .