EpistemisAlodynia
Specialty: Neurology.
Why it occurs
- Painful diabetic neuropathy (involvement of fine fibers)
- Postherpetic neuralgia (inflammatory sequelae of varicella-zoster virus infection)
- Complex regional pain syndrome (CRPS type I or II)
- Chronic migraine with central sensitization
- Chemotherapy-induced neuropathy (paclitaxel, oxaliplatin, vincristine)
- Demyelinating lesions or infarcts of the central spinothalmic pathways (central allodynia)
Initial workup
Directed sensory examination using a soft-bristle brush (dynamic allodynia) and a cotton-tipped applicator (static allodynia); electromyography and quantitative nerve conduction studies; skin biopsy to quantify intraepidermal nerve fiber density (if small fiber neuropathy is suspected with normal EMG); Brain MRI if there is suspicion of central origin (thalamus/trunk).
red flags
Hemigeneralized allodynia of sudden or progressive onset after a stroke (thalamic or Dejerine-Roussy pain syndrome), or lumbar/thoracic band allodynia associated with progressive weakness of the lower limbs or sphincter dysfunction (active myelopathy).
Standard management
- Amitriptyline — 10-75 mg at night, excellent central pain modulator
- Pregabalin — 75-600 mg/day in divided doses) or Gabapentin (300-3600 mg/day
- Lidocaine 5% or capsaicin 8% skin patch — indicated in localized allodynia due to postherpetic neuralgia
- Duloxetine (30-60 mg/day).
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Neurology
- Listed causes
- 6
- Treatment options
- 4