Extreme efficacy of intravenous immunoglobulin therapy for severe burning pain in a patient with small fiber neuropathy associated with primary Sjögren's syndrome.

Neurological involvement occurs in approximately 20% of patients with primary Sjögren's syndrome. Although neurological symptoms can affect the peripheral nervous system and the central nervous system, the most frequent symptom is polyneuropathy. Small fiber neuropathy (SFN) is a form of painful peripheral polyneuropathy that is common in patients with diabetic neuropathy, but may also occur in toxic, infectious, or immune-mediated neuropathy. We show here a patient with Sjögren's syndrome who developed SFN and was treated with intravenous immunoglobulin (IVIG) therapy, which was immediately and extremely effective. Because of the efficacy of IVIG therapy, we propose that direct immune-mediated mechanisms may be involved in the pathogenesis of SFN complicated by Sjögren's syndrome.