Impaired sweating as an exocrine manifestation in Sjögren's syndrome.

To examine the prevalence of hypohidrosis and to quantitate sweating as an exocrinopathy in Sjögren's syndrome (SS), 49 patients with SS (primary form, 38; secondary form, 11) were studied. Sweating was induced by mental stimulation such as deep breathing or hand grasping. Statistically significant reductions of sweat volume were seen in SS (P < 0.005). Patients under 50 years old showed impaired sweat function compared with normal controls (P < 0.0005). In a control study, only haemodialysis patients showed impairment of sweating and this was greater than in patients with SS aged under 50 years. These results suggest that patients with SS develop impaired sweating as an exocrine manifestation in addition to the known symptoms of xerostomia and xerophthalmus.