Skin sympathetic nerve activity in acquired idiopathic generalized anhidrosis.

We recorded skin sympathetic nerve activity (SSNA) microneurographically from the right tibial nerve of a patient with acquired idiopathic generalized anhidrosis (AIGA). The patient did not show any spontaneous sweating or pilocarpine- and nicotine-induced sweat response. Histopathologic examination showed degenerated eccrine glands associated with surrounding inflammatory cellular infiltration. Electrical nerve stimulation produced a two-peak pattern of SSNA reflex discharge representing sudomotor and vasoconstrictor components. The frequency of spontaneous SSNA bursts (burst rate), presumably of a sudomotor nature, at the ambient temperature of 25 degrees C was significantly higher than in a healthy control subject and was further increased at a temperature of over 38 degrees C. Thus, sudomotor sympathetic nerve activity is well preserved or even increased in AIGA. We conclude that anhidrosis of AIGA results from the generalized sweat gland dysfunction rather than decreased sympathetic outflow to the skin.