Selective loss of cholinergic sudomotor fibers causes anhidrosis in Ross syndrome.

Ross syndrome consists of segmental hyperhidrosis with widespread anhidrosis, Adie syndrome, and areflexia. The cause of this disorder is unknown. Selective degeneration of cholinergic fibers or of neural crest-derived structures has been suggested. We present clinical and skin biopsy data of 4 patients, providing evidence of reduced cholinergic sweat gland innervation in hypohidrotic skin by morphometric analysis. These findings indicate a selective degenerative process of the cholinergic sudomotor neurons.