Center for Pain Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
Department of Dermatology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
Br J Dermatol. 2018 Jul;179(1):154-162. doi: 10.1111/bjd.16217. Epub 2018 Apr 25.
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.
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.
Patients (n = 62) and controls (n = 45) completed the McGill and Douleur Neuropathique-4 (DN4) questionnaires. Sensory testing included detection and pain thresholds, pathological sensations, conditioned pain modulation (CPM) and temporal summation of pain.
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 DN4 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.
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 DN4 scores support this possibility and therefore neuropathic pain medications may be beneficial for patients with PC.
先天性厚甲症（PC）是一种罕见的常染色体显性遗传性皮肤病，以慢性疼痛为最突出的症状。组织学研究显示感觉神经支配的改变，以及对机械敏感性改变的报告表明，PC 可能是一种神经病变。
本文首次旨在系统评估 PC 患者与对照组之间的感觉功能，以研究 PC 的病理生理学。
患者（n=62）和对照组（n=45）完成了麦吉尔和神经病理性疼痛问卷 4（DN4）。感觉测试包括检测和疼痛阈值、病理性感觉、条件性疼痛调制（CPM）和疼痛的时间总和。
PC 患者（86%）的足部存在中度至重度慢性疼痛，疼痛性质为悸动性刺痛，尤其在承重时更为严重。此外，大多数患者的 DN4 评分≥4（62%），足部存在静态触诱发痛（55%）和刺痛感（53%）。与对照组相比，PC 患者的足部存在热觉和触觉减退以及机械性痛觉过敏。CPM 在患者中降低，且与足部机械性痛觉过敏增强相关。特定基因和致病突变的性质均不影响这些特征。
尽管热觉和触觉减退可能是由于皮肤增厚所致，但它们在疼痛区域的表现，以及机械性痛觉过敏和触诱发痛，提示 PC 中可能发生神经病变改变。临床特征和 DN4 评分支持这种可能性，因此神经病理性疼痛药物可能对 PC 患者有益。
