Complex regional pain syndrome (CRPS): when pain outlives the injury
Last updated September 3, 2026.
Complex regional pain syndrome (CRPS) is the condition where the pain after an injury (the often-minor one: the sprain, the fracture, the surgery) becomes severely disproportionate and persists: the burning, the extreme sensitivity (the bedsheet unbearable), with the swelling, the skin temperature-and-color changes, and the stiffness of the affected limb, usually the hand-or-foot. It is the nervous system malfunctioning (the pain system over-firing, not the ongoing tissue damage), it is uncommon, and the early diagnosis plus the physiotherapy-based rehabilitation gives the best chance of the recovery.
What does it look like?
The limb after the injury (the weeks-after kind), showing the cluster: the severe burning-or-stabbing pain far beyond the injury's explanation, the allodynia (the light touch hurting: the socks, the water, the air), the swelling and the stiffness, the skin changes (the red-or-mottled, the hot-or-cold, the sweaty, the shiny), the nail-and-hair changes, and the limb starting to be avoided (the not-moving-it feeding the cycle). It stays mostly the one limb, and the earlier it is caught, the better the odds.
Why does it happen?
The pain-system malfunction after the trigger (the injury, the fracture, the surgery, sometimes the trivial-or-absent trigger): the local nerves, the spinal cord, and the brain's pain-processing all shifting into the over-protection (the inflammation, the nerve-sensitivity, the brain's limb-map blurring), and the disuse deepening it (the not-moving-the-painful-limb reinforcing the whole loop). It is not the malingering, not the imagining: the changes are the measurable nervous-system biology.
How is it treated?
- The rehabilitation as the backbone: the physiotherapy and the occupational therapy (the graded re-use of the limb: the desensitization, the mirror therapy, the graded motor imagery, the gentle loading: the hardest and the most important part).
- The pain medicines as the enablers: the nerve-pain medicines (the amitriptyline-gabapentinoid kind), the short-course steroids for the early inflammatory kind, and the simple analgesia: the medicines making the rehabilitation possible, not replacing it.
- The psychology as the co-treatment, not the dismissal: the pain-management psychology (the fear-of-movement and the stress directly feed the pain system: the working-on-it is the physiological intervention).
- The specialist escalation: the pain-clinic options for the stubborn kind (the sympathetic blocks, the ketamine infusions, the spinal cord stimulation in the selected cases).
When does it need the prompt care?
The prompt review when the post-injury pain is worsening instead of settling (the weeks-2-to-4 window: the early treatment materially improves the odds), and the urgent help for the limb turning cold-dusky with the loss of function, or the mood collapsing (the CRPS carries the real depression-and-despair risk: the 988 lifeline in the US if it goes dark). Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
Is this pain real, or is it in my head?
Real, with the measurable biology: the CRPS involves the documented changes (the local inflammation, the nerve-sensitivity, the altered blood-flow control, and the brain-imaging-visible changes in the pain-processing and the limb-mapping), and the major pain-medicine bodies recognize it fully. The in-your-head framing is the outdated misunderstanding (the stress and the emotion modulate every pain condition, yours included: the modulation is not the invention), and the psychologists in the pain programs are the co-treaters of the nervous system, not the detectives of the faking.
The X-ray shows the bone healed. Why does it still hurt?
Because the CRPS pain is not coming from the bone anymore: the fracture healed (the X-ray is truthful), but the injury left the pain system malfunctioning (the nerves over-firing, the spinal cord amplifying, the brain's limb-representation blurring: the alarm stuck on after the fire is out), and that malfunction is the disease now, treatable by the retraining (the graded movement, the desensitization, the mirror work), not by the more bone-healing.
Will it spread or be permanent?
The honest spread of outcomes: the many improve substantially (especially with the early rehabilitation: the first-months treatment is the strongest prognostic factor), some have the fluctuating course for the longer, and the small minority develop the persistent severe kind (the reason the early aggressive rehabilitation is pushed). The spread to the other limb happens in the minority, and the avoiding-the-use is the biggest controllable risk factor for the worsening: the movement, however graded, is the medicine.
Why does water and even air hurt my hand?
The allodynia: the nervous system re-labeling the harmless touch as the pain (the sensitized nerves plus the spinal-brain amplification turning the shower droplets and the bedsheet into the threats), one of the CRPS hallmarks. The desensitization therapy targets it directly (the graded textures: the silk-to-towel progression, the minutes daily), and it responds: the sensitivity dial can be turned back down with the consistent retraining.
What is mirror therapy?
The brain-retraining trick with the real evidence: the good hand moves in front of the mirror positioned so the reflection looks like the painful hand moving (the brain receiving the moving-without-pain visual evidence for the affected side: the limb-map re-correcting), done in the short daily sessions, usually within the graded motor imagery program (the laterality exercises, then the imagining, then the mirror). It is the low-risk, the home-doable, and the well-studied kind.
How do I cope on the worst days?
The layered kit: the pain-medicine taken consistently (not the rescue-only), the pacing (the activity broken into the tolerable chunks, the boom-bust cycle avoided), the flare plan agreed with the therapist (the modified-not-stopped movement), the sleep protected (the pain-sleep-pain cycle feeds itself), and the mood watched honestly (the despair risk is the documented part of the CRPS: the 988 line if it darkens, the telling-the-team if it settles in). The worst days are the data for the team, not the verdicts.