Small vessel vasculitis in small fiber neuropathy: establishing clinical associations and identifying characteristics

Document Type

Conference Proceeding

Publication Date

10-16-2025

Publication Title

Clin Auton Res

Keywords

autoantibody, plexin, adult, cohort analysis, conference abstract, controlled study, epidermis, female, human, male, muscle cramp, prevalence, retrospective study, skin biopsy, small fiber neuropathy, small vessel vasculitis, therapy, vasculitis

Abstract

Objective: To identify the prevalence of vasculitis on skin biopsies in small fiber neuropathy (SFN), and to look for associations between vasculitis and known immune SFN (iSFN) clinical and pathological characteristics. Our hypothesis is that vasculitis is more prevalent than previously thought in SFN, and may be useful in identifying iSFN. Background: SFN is a painful syndrome that can be disabling, but up to 50% of cases are idiopathic. 19-35% of SFN cases may have an immune basis, but identifying such cases can be difficult. Recently, it was shown that 8.8% of skin biopsies in one population had vasculitis/ perifolliculitis, and that finding was associated with certain autoantibodies. Some of the patients had normal nerve epidermal nerve fiber density (ENFD) but had vasculitis, and abnormal autonomic studies. Design/Methods: Retrospective review of all SFN patients verified on skin biopsy from the same commercial laboratory and seen in the lead author's neuromuscular clinic (5/2023-11/2024). Clinical and pathological characteristics between vasculitic (VSFN) and non-vasculitic SFN (NVSFN) were statistically compared. Results: There were 65 patients (11 VSFN (17%), 54 NVSFN). There was a significant difference in muscle cramping between VSFN and NVSFN (91% vs. 57%, p = 0.0436). For the rest of the variables, there were no significant differences, including with TS-HDS, FGFR- 3, and Plexin-D1 antibodies. VSFN had higher SFN-screening list (SFNSL) score (48 vs. 36.5, p = 0.3059), early Sjogren antibodies (ESA) (60% vs. 38.3%, p = 0.2936), truncal symptoms (60% vs. 40.7%, p = 0.3116), acute/subacute onset (54.5% vs. 35.2%, p = 0.3111), and non-length dependent (NLD) ENFD (50% vs. 34.7%, p = 0.4490). Within the VSFN group, 1 patient had vasculitis at every biopsy site, and of the remaining 10, 90% had NLD-vasculitis; vasculitis was not associated with NLD-ENFD or acute/subacute onset (p = 1.0000). Conclusions: VSFN was more prevalent in our cohort and was associated with muscle cramps. Only trends existed with other iSFN characteristics; a larger cohort might show significant associations. NLD-vasculitic pattern was independent of ENFD and onset acuity, similarly to a prior study, suggesting proximal pathophysiology.

Volume

35

Issue

5

First Page

667

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