Small fiber neuropathy (SFN) is characterized by the involvement of Aδ and C fibers leading to sensory, mainly pain, and/or autonomic symptoms. Multiple chemical sensitivity syndrome (MCS) is an incompletely defined condition characterized by the onset of various symptoms in patients after exposure to several chemical substances. Pain is a common symptom in these patients. In this study, we report the histological and clinical data of a cohort of 21 patients who had been diagnosed as having MCS and who were referred to us with the suspicion of SFN because of chronic pain. All patients underwent neurological clinical examination, (including scales for pain and autonomic disorders), and a skin biopsy. Age-matched healthy subjects were used as controls for the skin biopsies. Nerve conduction studies and serum screening to exclude possible causes of peripheral neuropathy were also performed. Skin biopsies disclosed a somatic SFN in all patients. Although the majority (18 out of 21) of patients also had autonomic symptoms. we found sparing of autonomic innervation in the biopsies. These observations suggest that chronic pain in MCS could be secondary to the presence of somatic SFN, although more data are needed to confirm these observations.

中文翻译：

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慢性疼痛患者的小纤维神经病变和多种化学敏感性综合征的既往诊断

小纤维神经病变 (SFN) 的特征是涉及 Aδ 和 C 纤维，导致感觉症状，主要是疼痛和/或自主神经症状。多重化学敏感性综合征 (MCS) 是一种定义不完整的病症，其特征是患者在接触多种化学物质后会出现各种症状。疼痛是这些患者的常见症状。在这项研究中，我们报告了一组 21 名患者的组织学和临床数据，这些患者被诊断为患有 MCS，并且由于慢性疼痛而被怀疑为 SFN。所有患者都接受了神经系统临床检查（包括疼痛和自主神经紊乱量表）和皮肤活检。年龄匹配的健康受试者被用作皮肤活检的对照。还进行了神经传导研究和血清筛查以排除周围神经病变的可能原因。皮肤活检显示所有患者均存在体细胞 SFN。尽管大多数患者（21 人中有 18 人）也有自主神经症状。我们在活检中发现了自主神经支配。这些观察结果表明，MCS 中的慢性疼痛可能继发于躯体 SFN，尽管需要更多数据来证实这些观察结果。