Skin barrier structure and function and their relationship to pruritus in end-stage renal disease.

BACKGROUND The relationship between dry skin and uraemic pruritus remains controversial. In addition, there is a lack of published data describing the structure and function of the stratum corneum (SC) in end-stage renal disease (ESRD). The purpose of the present study was to assess the function and structure of the skin barrier in patients with ESRD and to correlate any abnormalities with uraemic pruritus. METHODS Thirty-eight subjects participated in the study; 20 with ESRD and 18 healthy controls. Subjects underwent evaluation of SC integrity and permeability barrier recovery, SC surface pH, pruritus and dry skin. The content of glycerol, an important endogenous humectant, was assessed in D-squame tape strips from seven patients with ESRD. Skin biopsies from six of these patients were examined by electron microscopy using ruthenium tetroxide (Ru04)-post-fixation. RESULTS Although SC integrity was impaired in ESRD patients (P = 0.001), there were no significant differences in permeability barrier recovery rates between ESRD subjects and controls. However, there was a high significant negative correlation between SC glycerol content and dry skin in the arms of ESRD subjects (r = -0.866, P = 0.01). Yet, there was no consistent correlation between pruritus and either dry skin, SC integrity, glycerol content or surface pH. Electron microscopy revealed no significant ultra-structural abnormalities, with particular reference to the lipid bi-layer. CONCLUSIONS SC integrity, but not permeability barrier recovery, is impaired in dialysis patients. Although dry skin in ESRD is associated with reduced SC glycerol levels, the ultra-structure appears to be unaffected.