Cutaneous involvement in severe carpal tunnel syndrome is secondary to damage to sensory and autonomic fibers of the median nerve. We report the case of a 63 year old man who presented skin and bone lesions, confined to the sensory zones of both median nerves. The lesions consisted of dystrophic modifications of the fingernails, progressive sclerosis, skin thickening and ulcerations on the fingers, acro-osteolysis, and purulent inflammation with subsequent auto-amputation of the distal phalanx of the right index finger. Clinical, neurophysiological and surgical findings are reported. The recovery of the ulcerative lesions suggests the reversibility of autonomic disturbances after surgery.