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Chronic pain in pachyonychia congenita: evidence for neuropathic origin
Author(s) -
Brill S.,
Sprecher E.,
Smith F.J.D.,
Geva N.,
Gruener H.,
NahmanAverbuch H.,
Defrin R.
Publication year - 2018
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.16217
Subject(s) - medicine , neuropathic pain , allodynia , hyperalgesia , pathophysiology , pathological , neuralgia , anesthesia , chronic pain , dermatology , nociception , physical therapy , receptor
Summary Background Pachyonychia congenita ( PC ) is a rare autosomal dominant skin disease, with chronic pain being the most prominent complaint. Histological studies showing alterations in sensory innervation, along with reports on alterations in mechanical sensitivity, suggest that PC may be a form of neuropathy. Objectives Here, for the first time, we aim to evaluate systematically the sensory function of patients with PC vs. controls, in order to investigate the pathophysiology of PC . Methods Patients ( n = 62) and controls ( n = 45) completed the McGill and Douleur Neuropathique‐4 ( DN 4) questionnaires. Sensory testing included detection and pain thresholds, pathological sensations, conditioned pain modulation ( CPM ) and temporal summation of pain. Results A moderate‐to‐severe chronic pain in the feet, throbbing and stabbing in quality, was highly prevalent among patients with PC (86%) and was especially debilitating during weight bearing. In addition, the majority of patients had a DN 4 score ≥ 4 (62%), static allodynia (55%) and tingling (53%) in the feet. Compared with controls, patients with PC exhibited thermal and mechanical hypoaesthesia and mechanical hyperalgesia in the feet. CPM was reduced among the patients, and was associated with more enhanced mechanical hyperalgesia in the feet. The specific gene and nature of the causative mutation did not affect any of these features. Conclusions Although thermal and mechanical hypoaesthesia may result from thicker skin, its presentation in painful regions, along with mechanical hyperalgesia and allodynia, point towards the possibility of neuropathic changes occurring in PC . The clinical features and DN 4 scores support this possibility and therefore neuropathic pain medications may be beneficial for patients with PC .