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Background: Vasculitic neuropathy is a common manifestation of Churg-Strauss syndrome (CSS).The pathological process of nerve damage in vasculitic neuropathy is characterized primarily by axonal degeneration and to a lesser extent by demyelination due to nerve ischemia secondary to small-vessel vasculitis.Here we aimed to evaluate the incidence of demyelination and axonal degeneration on sural nerve biopsies in CSS, and address the extent to which ischemia due to vasculitis correlates demyelinating injuries.Patients and Methods: We studied sural nerve biopsies of 22 CSS patients.Myelinated fiber densities (MFDs) were measured in semithin sections.Teased fiber analysis was used to identify nerve fiber conditions denoting normal, axonal degeneration and demyelination.The incidence of each condition as a percentage of the total number of teased fibers was calculated for individual patients.Results: Histologically, demyelination was more prominent than axonal degeneration in patients with mild MFD reduction.The mean MFD decreased to 3899 ± 2429/mm2.The average percentages of normal, demyelination, and axonal degeneration among teased fibers were 16.7 ± 19.9%, 28.4 ± 18.7%, and 55.2 ± 33.5%.MFD was positively correlated with the percentage of demyelination and negatively correlated with the percentage of axonal degeneration.Conclusion: We demonstrated vasculitic neuropathy in CSS exhibited significant demyelination, and its incidence increased significantly in parallel with MFD size, suggesting that a mild degree of ischemia triggered the demyelinating process in preference to axonal degeneration.Understanding the demyelinating process due to ischemia may provide new insights into therapeutic strategies that target Schwann cells for vasculitic neuropathy.