Table 2Classification of Chronic Pain Syndromes and Relationship to Neurobiologic Mechanism of Pain

Pain TypeDefinitionNeurobiologic MechanismExamples
Chronic Primary Pain
 1. Chronic widespread painWidespread pain persisting for longer than 3 months, associated with emotional distress or functional disabilityCentral sensitizationFibromyalgia
 2. Complex Regional Pain SyndromeDisorder of body region, usually distal limbs, characterized by pain (allodynia), swelling, loss of function, vasomotor instability, skin changesNeuropathic
Central sensitization		Chronic Regional Pain Syndrome (formerly reflex sympathetic dystrophy)
 3. Chronic primary headache/orofacial painIdiopathic headache or orofacial pain, not secondary to another conditionNociceptive
Neuropathic
Central sensitization		Chronic migraine or temporomandibular disorder
 4. Chronic primary visceral painPersistent or recurrent pain originating from internal organs, without a clear organic causeCentral sensitizationIrritable bowel syndrome
 5. Chronic primary musculoskeletal painChronic pain experienced in muscles, bones, joints, or tendons that cannot be attributed directly to a known disease or tissue damage process2Nociceptive
Neuropathic
Central sensitization		Non-specific low back pain
Chronic Secondary Pain
 1. Chronic cancer-related painPain caused by the cancer itself (by the primary tumor or by metastases) or by its treatment (surgery, chemotherapy, or radiotherapy)3Nociceptive
Neuropathic
Central sensitization		Chronic cancer pain, chronic cancer treatment pain (eg, chemotherapy-induced peripheral neuropathy, radiation fibrosis)
 2. Chronic postsurgical or posttraumatic painPain secondary to surgery or trauma which persists for longer than 3 monthsNociceptive
Neuropathic
Central sensitization		Incisional pain, nerve injury due to trauma or surgery (eg, persistent whiplash or low back pain after trauma)
 3. Chronic neuropathic painPain caused by a lesion or disease of the somatosensory nervous system5NeuropathicTrigeminal neuralgia, chronic painful polyneuropathy (eg, diabetic polyneuropathy), postherpetic neuralgia
 4. Chronic secondary headache/orofacial painHeadaches or orofacial pains, secondary to a medical conditionNociceptive
Neuropathic
Central sensitization		Head/face pain secondary to trauma, tumor, hemorrhage, etc.
 5. Chronic secondary visceral painPersistent or recurrent pain originating from internal organs, due to a secondary causeNociceptiveAbdominal pain due to adhesions or ischemia
 6. Chronic secondary musculoskeletal painPersistent or recurrent pain that arises as part of a disease process directly affecting bones, joints, muscles, or related soft tissuesNociceptiveRheumatoid arthritis, osteoarthritis

Note: Adapted from Treede, RD, Rief w, Barke A, et.al, Chronic pain as a symptom or disease: the IASP classification of chronic pain for the International Classification of Diseases (ICD-11. Pain, Jan 2019, 160 (1):19-271

From: Pain Management

Cover of Pain Management
Pain Management [Internet].
Fenske JN, Berland DW, Chandran SK, et al.
Ann Arbor (MI): Michigan Medicine University of Michigan; 2021 Jan.
© Regents of the University of Michigan.

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