Why classify pain?
An anti-inflammatory works remarkably well for a sprained ankle and has almost no effect on nerve pain. Conversely, an anti-epileptic such as pregabalin is useless in acute inflammatory pain yet can transform daily life for someone with diabetic neuropathy. The mechanism dictates the treatment — which is why a doctor spends as much time asking about the quality of the pain as examining the area that hurts.
1. Nociceptive pain
This is “normal” pain: the alarm system doing its job. Specialised receptors called nociceptors detect mechanical, thermal or chemical injury and pass the signal on to the spinal cord and then the brain.
It divides into two families:
- Somatic pain — arising from skin, muscle, tendon, bone or joint. It is well localised, described as an ache, a throb or a surface burn, and it changes with movement. Examples: fracture, sprain, osteoarthritis, a wound.
- Visceral pain — arising from the internal organs. It is dull, diffuse and poorly localised, often with nausea, sweating and restlessness. Examples: renal colic, peptic ulcer, bowel obstruction, period pain.
This kind of pain usually responds well to paracetamol, NSAIDs, antispasmodics for the visceral type, and opioids when it is severe.
2. Neuropathic pain
Here the damage affects the nervous system itself, either in the periphery (nerve, root, plexus) or centrally (spinal cord, brain). The pain signal is produced without any outside stimulus: the cable is damaged and fires on its own.
Patients' own words are highly suggestive: burning, painful cold, electric shocks, tingling, pins and needles, numbness, itching. Two clinical signs are characteristic:
- allodynia, pain triggered by contact that is normally painless — a bedsheet, clothing, a draught of air;
- hyperalgesia, an exaggerated and prolonged response to a stimulus that is already painful.
The commonest causes are diabetic neuropathy, post-herpetic neuralgia after shingles, radiculopathy from a prolapsed disc, chemotherapy-induced neuropathy, division of a nerve during surgery, multiple sclerosis, stroke, and phantom limb pain after amputation.
3. Nociplastic pain
Formally recognised by the IASP in 2017, this third category describes pain arising from a lasting change in the way the nervous system processes signals, with no demonstrable damage to tissue or nerve.
The central phenomenon is called central sensitisation: neurons in the spinal cord and brain become hyperexcitable, the descending inhibitory filter weakens, and ordinary signals are read as painful. The volume on the alarm system has been turned up and no longer comes back down.
Typical presentations include fibromyalgia, non-specific chronic low back pain, irritable bowel syndrome, chronic tension-type headache, interstitial cystitis and complex regional pain syndrome. This kind of pain very often comes with fatigue, disturbed sleep and difficulty concentrating.
Recognising the mechanism in practice
| Feature | Nociceptive | Neuropathic | Nociplastic |
|---|---|---|---|
| Description | Aching, throbbing, cramping | Burning, shooting, tingling | Widespread pain, shifting, persistent |
| Distribution | Over the injured area | In the territory of a nerve or root | Extensive, often on both sides |
| Examination | Pain on pressure or on movement | Altered sensation, allodynia | Few objective signs, thresholds lowered everywhere |
| Imaging | Often informative | May show the nerve lesion | Normal |
| First-line treatment | Paracetamol, NSAIDs, movement | Anti-epileptics, antidepressants, topical agents | Graded exercise, education, CBT |
Particular forms worth knowing
Referred pain
Felt at a distance from the affected organ because the nerve pathways converge in the spinal cord: left arm and jaw pain during a heart attack, right shoulder pain coming from the gallbladder, knee pain that turns out to come from the hip.
Phantom limb pain
Up to eight in ten people who have had an amputation feel pain in the missing limb. It reflects the persistence of the limb's map in the brain; mirror therapy and graded motor imagery are among the answers.
Breakthrough pain
A brief, intense flare occurring despite well-controlled background treatment, and common in cancer pain. It needs a fast-acting rescue medicine, prescribed in advance.
Procedure-related pain
Caused by a dressing change, a needle, being moved or transferred. It is predictable and therefore preventable: it is headed off before the procedure, never afterwards.
Frequently asked questions
Can you have more than one type of pain at the same time?
Yes, and in chronic conditions it is the rule rather than the exception. It is called mixed pain. Sciatica typically combines a nociceptive component (the disc and the muscles) with a neuropathic one (the compressed root); after several months a nociplastic component is often added.
How do I know whether my pain is neuropathic?
The DN4 questionnaire, used in the consulting room, has ten items covering the description of the pain and the examination of sensation. A score of at least 4 out of 10 makes the diagnosis very likely and points towards specific treatment.
Is nociplastic pain the same as psychological pain?
No. The mechanisms involved are neurobiological and can be measured in research settings: amplification of signals, failure of descending inhibition, changes in brain networks. Psychological factors and stress modulate the intensity, as they do in every kind of pain, but they are not the sole cause.
Can chronic pain go away?
Full recovery is possible, particularly when care starts early and addresses the whole person. But the realistic goal of treatment is often a meaningful reduction in intensity together with a return of function, sleep and the activities that matter.
Sources and references
- Kosek E. et al., Chronic nociplastic pain affecting the musculoskeletal system, Pain, 2021.
- Finnerup N. B. et al., Neuropathic pain: an updated grading system, Pain.
- IASP — Terminology: allodynia, hyperalgesia, nociception, sensitisation.
- Bouhassira D. et al., Comparison of pain syndromes: development of the DN4 questionnaire.