• Clinical science



Fibromyalgia (FM) is a neurosensory disorder characterized by chronic musculocutaneous pain. The etiology and pathogenesis of this condition are not fully understood, but, notably, there is no identifiable inflammation that causes the musculocutaneous symptoms. Patients typically present with functional symptoms (e.g., fatigue, unrefreshing sleep, morning stiffness) and often have a history of psychiatric disorders (e.g., depression, generalized anxiety disorder). Physical examination reveals characteristic tender points over multiple areas of the body with no signs of inflammation (i.e., no notable swelling, deformity, or erythema). Findings from laboratory tests are normal. Although this disorder is benign, it causes patients significant psychological strain and discomfort. Treatment focuses on lifestyle changes and multidisciplinary pain management.


  • Prevalence: 2–3% [1]
  • Sex: > (2:1) [2]
  • Peak incidence: 20–50 years (risk of occurrence increases with age)

Epidemiological data refers to the US, unless otherwise specified.


The pathophysiology of FM is not fully understood, but its etiology is likely multifactorial. The interaction of the following factors may play a role:

  • Genetic predisposition
  • Environmental triggers (e.g., physical or psychosocial stress)
  • Dysregulation of the neuroendocrine and autonomic nervous systems


Clinical features

Common symptoms

Common associations

The following disorders can manifest with symptoms that sometimes resemble those seen in FM, and these conditions may occur alongside FM.



  • FM is a clinical diagnosis.
    • The 2010 American College of Rheumatology (ACR) criteria take into account:
      • Symptom duration of at least 3 months
      • Patient self-reporting using the fibromyalgia score :
        • Widespread pain or tenderness in up to 19 different regions of the body (widespread pain index; WPI)
        • Presence and severity of symptoms such as fatigue, sleep disturbance, depression, headache, and cognitive impairment (symptom severity scale)
    • Traditionally, a tender-point examination was performed based on the 1990 ACR diagnostic criteria :
      • Symptom duration of at least 3 months
      • Tender points: ≥ 11 of 18 FM-associated localized areas of pain
      • Pain-affected areas: all four quadrants of the body
  • Laboratory values and imaging findings are normal (helpful for excluding other causes or comorbidities).

A combined assessment of the number, duration, and severity of cognitive and somatic symptoms provides the most accurate diagnosis.References:[4][10][11][12][13]

Differential diagnoses


The differential diagnoses listed here are not exhaustive.


Initial approach