Efficacy of intravenous immunoglobulin for small fiber neuropathy associated with sarcoidosis

Background: Small fiber neuropathy (SFN) is commonly associated with sarcoidosis and can cause significant morbidity to afflicted patients. The appropriate treatment of this condition, when associated with sarcoidosis, is not well established. Methods: Descriptive case series of three patients with sarcoidosis and SFN. The presenting clinical features, skin biopsy results, autonomic reflex screen and quantitative sudomotor axon reflex testing (QSART) findings, and response to therapy are delineated. Results: We describe three patients with biopsy-proven sarcoidosis who developed intractable neuropathic pain and/or symptoms related to associated autonomic dysfunction despite treatment with various immunosuppressive medications and narcotic analgesics. QSART showed evidence of a postganglionic sudomotor abnormality in one patient and was normal in the other two. Skin biopsy findings were abnormal, demonstrating a non-length-dependent sensory SFN in all three patients. Painful neuropathic symptoms, as well as symptoms related to dysautonomia from SFN responded significantly to treatment with intravenous immunoglobulin (IVIG). Conclusion: IVIG appears to be effective in relieving symptoms from SFN associated with sarcoidosis, suggesting an underlying immune mechanism. Larger prospective, controlled studies would be needed to confirm this response to IVIG and to further elucidate the underlying pathobiology behind this association with sarcoidosis.