Sweat secretion, stratum corneum hydration, small nerve function and pruritus in patients with advanced chronic renal failure

Sweat secretion, stratum corneum hydration and small nerve fibre function were measured in 40 patients with advanced chronic renal failure (CRF), using pilocarpine iontophoresis, electrical capacitance and a thermal sensory analyser which measures the thresholds of warm and heat pain sensation. Correlations were sought between these parameters, and the presence and severity of pruritus and skin xerosis were compared with 45 healthy control subjects. The mean sweat secretion and stratum corneum hydration of CRF patients were significantly lower than in controls. Thirteen patients had pathological thresholds to warm sensation on the foot, and eight on the hand. None had pathological thresholds to heat-pain. The presence of pruritus did not correlate with any of the following: xerosis, stratum corneum hydration, sweat secretion or the results of thermal testing.