Neuropathic pain in post-burn hypertrophic scars: apsychophysical and neurophysiological study

Introduction: Pain complicates hypertrophic post-burn pathologic scars (PPS) Methods: To investigate the possible neuropathic origin of pain, 13 patients with painful PPS involving at least 1 hand underwent clinical examination, including the Douleur Neuropathique en 4 questions (DN4) questionnaire; median, ulnar, and radial nerve conduction studies (NCS); cold- (CDT) and heat-induced pain threshold evaluation by quantitative sensory testing; and cutaneous silent period (CSP) testing of the abductor pollicis brevis. Controls included 9 patients with non-painful PPS, 52 healthy subjects, and 28 patients with carpal tunnel syndrome (CTS). Results: All patients with painful PPS had possible neuropathic pain (DN4 score ≥4). NCS signs of CTS were similarly present in PPS subjects with or without pain. Hands with painful PPS had lower CDT and CSP duration, more frequent cold- and heat-pain hypesthesia, and more thermal allodynia than controls. Conclusions: In PPS, possible neuropathic pain is associated with psychophysical and neurophysiological abnormalities suggestive of small-fiber damage.