Autoimmune or possibly infectious (but with no specific causal infectious agent identified)

• Sarcoidosis
• Guillain-Barré Syndrome / Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
• Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
• Vasculitis

- Polyarteritis Nodosa (PAN)

- Rheumatoid Arthritis

- Systemic Lupus Erythematosus (Lupus)

- Sjögren's Syndrome

• Celiac Disease
• Multifocal Motor Neuropathy (MNN)
• Peripheral Neuropathy Associated with Protein Abnormalities

- Monoclonal Gammopathy

- Amyloidosis

- Cryoglobulinemia

- POEMS