Author Response: Intravenous Immunoglobulin Therapy in Patients With Painful Idiopathic Small Fiber Neuropathy.

Abstract

We would like to respond to the comments made by Drs. Wilder-Smith and Spoendlin on our study1 related to the heterogeneous group of patients with idiopathic small fiber neuropathy (I-SFN), who might benefit from intravenous immunoglobulin (IVIg) therapy. Before study entry, all patients had a diagnostic SFN workup, which includes tests for several associated conditions, as mentioned in the inclusion criteria.1 Of 257 patients, there were 193 patients who did not meet the inclusion criteria, 41 of which (16%) were excluded because of known autoimmune conditions, which is in line with previous findings.2 Future studies are needed to definitely determine whether IVIg may have a therapeutic role in the treatment of autoimmune conditions that cause SFN. There are some open-label clinical studies suggesting a potential therapeutic role,3,4 but stronger evidence from a randomized study is needed. Our RCT showed that IVIg treatment had no significant effect on pain in patients with painful I-SFN and should therefore be discouraged.