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Neuropathic pain — overview

TL;DR — Neuropathic pain requires a lesion or disease of the somatosensory system; descriptors such as “burning” alone do not establish it. The NeuPSIG grading system moves from possible to probable to definite using neuroanatomically plausible history, sensory signs and objective confirmation (Finnerup 2016, PMID 27115670). Mechanisms differ among patients and include ectopic peripheral firing, neuroimmune activation, spinal disinhibition and central sensitization (Colloca 2017, PMID 28205574). First-line drugs have modest average effects, so treatment is iterative and function-focused (Finnerup 2015, PMID 25575710). No biomarker currently selects an effective drug, and invasive neuromodulation benefits selected refractory groups while introducing procedural risk (Petersen 2021, PMID 33818600).

Definition and diagnostic anchors

  • Neuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system.
  • Possible: a relevant neurological lesion/disease history and neuroanatomically plausible pain distribution.
  • Probable: plus sensory signs within the same distribution.
  • Definite: plus a test confirming the lesion/disease that explains the pain (Finnerup 2016, PMID 27115670).
  • Spine-related leg pain is not automatically neuropathic; radicular pain, radiculopathy and referred pain require distinct terminology and evidence (Schmid 2023, PMID 37235637).
  • Burning, tingling, shocks, allodynia and numbness are clues, not sufficient proof. Examination maps negative and positive sensory signs.

European assessment guidance integrates history, neurological examination, questionnaires, neurophysiology, imaging, skin biopsy and QST according to the suspected lesion (Truini 2023, PMID 37253688).

Epidemiology and burden

A systematic review of general-population studies estimated prevalence at 6.9–10% using validated screening tools, with heterogeneity from instruments and populations (van Hecke 2014, PMID 24291734). The category spans painful diabetic neuropathy, postherpetic neuralgia, trigeminal neuralgia, postsurgical/traumatic nerve pain, chemotherapy-induced neuropathy, radiculopathy and central pain after spinal cord injury, stroke or multiple sclerosis.

Neuropathic pain is associated with sleep disruption, depression/anxiety, impaired mobility and work, but burden differs by cause, distribution and sensory phenotype. Chronic-pain reviews emphasize that access and opioid exposure add system-level harms (Cohen 2021, PMID 34062143).

The denominator and case definition materially change every headline estimate. For example, an updated spinal-cord-injury meta-analysis included 24 studies and 6,318 participants and estimated pooled neuropathic-pain prevalence at 57% (95% CI 51–64%), but heterogeneity was extreme (I²=96.2%); prevalence was 30% for below-level pain, 20% for at-level pain and 5% for combined at- and below-level pain, and classification system independently affected the estimate (Salehian 2025, PMID 41043376). These figures should therefore be read as syndrome- and method-specific, not as interchangeable fractions of one disease.

Mechanism sketch

Peripheral generators

Nerve injury changes sodium, potassium and calcium channels, produces ectopic discharges in axons and dorsal-root ganglia, alters sympathetic coupling and recruits macrophage/Schwann-cell signaling. Surviving nociceptors can become hyperexcitable (Baron 2010, PMID 20650402; Cohen 2014, PMID 24500412).

Small-fiber neuropathy can cause distal or non-length-dependent pain with normal routine nerve-conduction studies. Diagnosis combines phenotype with skin biopsy, thermal thresholds or autonomic testing; etiologic workup remains essential (Devigili 2020, PMID 32654574).

Human channelopathies provide unusually direct causal evidence: loss-of-function variants in SCN9A/NaV1.7 can abolish pain, whereas gain-of-function variants cause erythromelalgia, paroxysmal extreme pain disorder or small-fiber neuropathy; NaV1.8, NaV1.9 and TRPA1 variants broaden the genotype–phenotype map (Comini 2024, PMID 39174256). This genetic clarity has not translated into a universal channel-blocker strategy because acquired neuropathies involve multiple channels, cell types and injury states.

Central amplification

Sustained input can potentiate spinal and supraspinal circuits, reduce inhibition and expand receptive fields, producing allodynia and hyperalgesia. Central sensitization is a mechanism, not a synonym for every chronic pain condition (Latremoliere 2009, PMID 19712899; Woolf 2011, PMID 20961685).

Mechanism reviews emphasize that the same etiology can generate different phenotypes and the same phenotype can arise from different lesions—one reason diagnosis does not directly dictate drug response (Finnerup 2021, PMID 32584191).

Treatment landscape

Pharmacotherapy

NeuPSIG meta-analysis recommended tricyclic antidepressants, SNRIs, pregabalin and gabapentin as first-line options, with topical lidocaine/capsaicin and tramadol in selected second-line contexts and strong opioids generally later-line (Finnerup 2015, PMID 25575710).

Treatment Evidence boundary
Gabapentin Some people with postherpetic neuralgia or painful diabetic neuropathy achieve substantial relief; many do not, and dizziness/somnolence are common (Wiffen 2017, PMID 28597471)
Pregabalin Efficacy varies by condition and dose; adverse-event withdrawals matter (Derry 2019, PMID 30673120)
Duloxetine Evidence supports painful diabetic neuropathy, with smaller evidence bases in other pain states (Lunn 2014, PMID 24385423)
Capsaicin 8% patch Localized peripheral pain can improve after supervised application; application pain and variable duration limit use
Opioids Chronic noncancer-pain meta-analysis found small average improvements with frequent adverse effects and limited long-term evidence (Busse 2018, PMID 30561481)

Because monotherapy response is incomplete, combination strategies are common. OPTION-DM evidence supports several pathway combinations for painful diabetic neuropathy when initial monotherapy is inadequate, with tolerability guiding sequence (Saul 2023, PMID 37085164).

Etiology-specific and nonpharmacologic care

Glycemic and risk-factor management addresses diabetic neuropathy progression but does not reliably reverse established pain; diabetic neuropathy is a multi-pathway metabolic and microvascular disease (Feldman 2019, PMID 31197153).

For chemotherapy-induced peripheral neuropathy, ASCO found no proven preventive drug and supports duloxetine for established painful CIPN, while emphasizing chemotherapy-dose decisions and function (Loprinzi 2020, PMID 32663120).

Psychological, sleep, activity and rehabilitation approaches do not imply pain is psychogenic; they target amplification, disability and coping alongside lesion-directed care. French multidisciplinary recommendations integrate drug and non-drug options while grading weak evidence explicitly (Moisset 2020, PMID 32276788).

Neuromodulation

In refractory painful diabetic neuropathy, 10-kHz spinal-cord stimulation plus conventional medical management produced more responders than medical management alone at 6 months, with device/procedure adverse events and selected eligibility (Petersen 2021, PMID 33818600). Durability, explant/infection burden, cost and generalization beyond the studied phenotype require ongoing evaluation (Petersen 2023, PMID 38245324).

Measurement and biomarkers

QST can characterize thermal and mechanical gain/loss using standardized reference values but depends on attention and cannot localize a lesion alone (Rolke 2006, PMID 16697110). Skin biopsy measures small-fiber density; neurophysiology tests large fibers; neither directly measures pain.

EEG biomarker review found heterogeneous resting-state candidates without a validated diagnostic or treatment-predictive signature (Mussigmann 2022, PMID 35659993). Phenotyping is therefore useful for research and differential diagnosis but not yet a proven prescribing algorithm.

Screening performance is also setting-dependent. In the original back-pain development program, paper painDETECT achieved 85% sensitivity, 80% specificity and 83% positive predictive accuracy, but those values were generated in the instrument's intended case mix (Freynhagen 2006, PMID 17022849). In a community validation, mailed S-LANSS sensitivity was only 57% (95% CI 46–69%) and specificity 69% (95% CI 61–77%); telephone administration yielded 52% (95% CI 39–64%) and 78% (95% CI 68–85%), respectively (Weingarten 2007, PMID 17869424). The contrast is a concrete warning against treating questionnaire-positive prevalence as lesion-confirmed neuropathic pain.

Research frontier

  • Mechanism-based treatment selection using sensory phenotype rather than etiology alone.
  • Rational combinations that increase responder rates without compounding sedation and falls.
  • Disease-modifying treatment for diabetic, toxic and immune neuropathies rather than analgesia alone.
  • Long-term comparative safety and cost-effectiveness of SCS and other devices.
  • Biomarkers that predict response and are robust across centers (Mussigmann 2022, PMID 35659993).

Evidence interpretation map

The table makes the evidence role and inferential boundary explicit; it is not a replacement for the full reports.

PMID Year Evidence role What it cannot establish alone
41043376 2025 Updated SCI prevalence meta-analysis A universal prevalence independent of classification system
39174256 2024 Human channelopathy synthesis That acquired neuropathic pain is monogenic or channel-selective
17022849 2006 painDETECT development/validation Definite neuropathic pain in unselected populations
17869424 2007 Community S-LANSS validation Lesion localization or etiology

Minimum reporting controls

Domain Required report
Case definition Possible, probable or definite neuropathic pain
Etiology Lesion/disease and diagnostic evidence
Distribution Focal, length-dependent, dermatomal, at-level or below-level
Baseline phenotype Negative and positive sensory signs
Comparator Placebo/sham, active care or natural history
Exposure Dose, duration, adherence and co-interventions
Benefit Mean change plus ≥30% and ≥50% responders where applicable
Function Sleep, mobility, participation and patient global change
Harm Adverse events, withdrawals and serious events
Durability Follow-up after treatment and attrition
Subgroups Prespecified interaction test, not within-group significance
Missingness Denominator and imputation method

Reporting cautions

  • Do not infer lesion presence from a symptom descriptor.
  • Do not convert a group-average association into an individual diagnostic rule.
  • Do not treat statistical significance as clinically important benefit.
  • Do not compare NNTs without checking outcome threshold, duration and population.
  • Do not interpret an inactive or completed registry record as proof of efficacy.
  • Do not merge painful and painless neuropathy outcomes.
  • Do not omit adverse-event withdrawals from responder interpretation.
  • Do not call a post hoc subgroup predictive without an interaction test.
  • Do not generalize a focal peripheral result to central neuropathic pain.
  • State when evidence is short-term, indirect or restricted to a selected cohort.

Open questions

  • Can QST or sensory clusters predict which drug will work? (Rolke 2006, PMID 16697110; Finnerup 2021, PMID 32584191)
  • Which combination sequence maximizes benefit without additive adverse effects? (Saul 2023, PMID 37085164)
  • Can painful diabetic neuropathy be modified rather than symptomatically suppressed? (Feldman 2019, PMID 31197153)
  • Does SCS retain net benefit over years after infections, revisions and explants are counted? (Petersen 2021, PMID 33818600; Petersen 2023, PMID 38245324)
  • What validated marker separates peripheral drive from maintained central amplification? (Woolf 2011, PMID 20961685; Mussigmann 2022, PMID 35659993)

References

  1. Finnerup NB, et al. Neuropathic pain: updated grading system. Pain. 2016. PMID 27115670
  2. Schmid AB, et al. Neuropathic pain terminology in spine-related leg pain. Pain. 2023. PMID 37235637
  3. Truini A, et al. EAN–EFIC–NeuPSIG guidelines on neuropathic-pain assessment. Eur J Neurol. 2023. PMID 37253688
  4. van Hecke O, et al. Neuropathic pain in the general population. Pain. 2014. PMID 24291734
  5. Cohen SP, et al. Chronic pain: burden, best practices and advances. Lancet. 2021. PMID 34062143
  6. Colloca L, et al. Neuropathic pain. Nat Rev Dis Primers. 2017. PMID 28205574
  7. Baron R, et al. Neuropathic pain: diagnosis, mechanisms and treatment. Lancet Neurol. 2010. PMID 20650402
  8. Cohen SP, et al. Neuropathic pain mechanisms and implications. BMJ. 2014. PMID 24500412
  9. Finnerup NB, et al. Neuropathic pain: from mechanisms to treatment. Physiol Rev. 2021. PMID 32584191
  10. Latremoliere A, et al. Central sensitization and pain hypersensitivity. J Pain. 2009. PMID 19712899
  11. Woolf CJ. Central sensitization: diagnosis and treatment implications. Pain. 2011. PMID 20961685
  12. Devigili G, et al. Clinical diagnosis and management of small-fiber neuropathy. J Peripher Nerv Syst. 2020. PMID 32654574
  13. Finnerup NB, et al. Pharmacotherapy for neuropathic pain in adults. Lancet Neurol. 2015. PMID 25575710
  14. Wiffen PJ, et al. Gabapentin for chronic neuropathic pain. Cochrane Database Syst Rev. 2017. PMID 28597471
  15. Derry S, et al. Pregabalin for neuropathic pain. Cochrane Database Syst Rev. 2019. PMID 30673120
  16. Lunn MP, et al. Duloxetine for painful neuropathy and chronic pain. Cochrane Database Syst Rev. 2014. PMID 24385423
  17. Busse JW, et al. Opioids for chronic noncancer pain. JAMA. 2018. PMID 30561481
  18. Saul H, et al. Combination therapy for painful diabetic neuropathy. BMJ. 2023. PMID 37085164
  19. Feldman EL, et al. Diabetic neuropathy. Nat Rev Dis Primers. 2019. PMID 31197153
  20. Loprinzi CL, et al. ASCO chemotherapy-induced peripheral neuropathy guideline update. J Clin Oncol. 2020. PMID 32663120
  21. Moisset X, et al. Pharmacological and non-pharmacological neuropathic-pain treatments. Rev Neurol. 2020. PMID 32276788
  22. Petersen EA, et al. 10-kHz spinal-cord stimulation in painful diabetic neuropathy. JAMA Neurol. 2021. PMID 33818600
  23. Petersen EA, et al. Spinal-cord stimulation in painful diabetic neuropathy: overview. J Diabetes Sci Technol. 2023. PMID 38245324
  24. Rolke R, et al. DFNS quantitative sensory testing protocol. Eur J Pain. 2006. PMID 16697110
  25. Mussigmann T, et al. EEG biomarkers of chronic neuropathic pain. Pain. 2022. PMID 35659993
  26. Salehian F, et al. Prevalence of neuropathic pain following spinal cord injury: An updated systematic review and meta-analysis. J Clin Neurosci. 2025;142:111660. PMID 41043376
  27. Comini M, et al. Human pain channelopathies. Handb Clin Neurol. 2024;203:89-109. PMID 39174256
  28. Freynhagen R, et al. painDETECT: a new screening questionnaire to identify neuropathic components in patients with back pain. Curr Med Res Opin. 2006;22:1911-1920. PMID 17022849
  29. Weingarten TN, et al. Validation of the S-LANSS in the community setting. Pain. 2007;132:189-194. PMID 17869424