An acquired disorder affecting predominantly large-fiber sensory peripheral axons. This neuropathy typically affects patients in middle age, and, while it may present acutely or subacutely, it is likely to remain for many years and not respond well to therapy. Neurophysiologic and pathological studies reveal axonal degeneration of large-diameter sensory axons. Upon biopsy, inflammatory foci are often found in dorsal root ganglia. Idiopathic sensory ganglionitis can only be distinguished from that associated with Sjogren syndrome or small cell carcinoma of the lung by excluding these two disorders.