Etiopathogenesis of uraemic pruritus remains unclear. In the present study, including 119 chronic haemodialysis patients, the correlation between pruritus and methods of haemodialysis and associated metabolic abnormalities was evaluated. In addition in 32 patients cutaneous mast cells were studied using enzymocytochemical methods. Pruritus was found in 58.8% of the patients. In the pruritic haemodialysis patients serum calcium concentrations were significantly increased. Moreover, serum phosphorus concentrations were also evidently elevated in the patients with pruritus. Pruritus was found to be more common in patients with a longer haemodialysis period and in patients haemodialysed using less permeable cuprophane dialyzers compared to those dialysed using polysulphone dialyzers. No correlation was demonstrated between the frequency and intensity of pruritus and the type of dialysate, erythropoietin intake, age and sex of patients, underlying renal disease, degree of anaemia and serum concentrations of urea, creatinine, sodium, potassium, magnesium, parathormone and alkaline phosphatase. In the haemodialysis patients the mean number of cutaneous mast cells was significantly higher compared to healthy individuals. No correlation was found with the number of mast cells and duration of haemodialysis period, the serum concentrations of calcium, phosphorus, magnesium and parathormone. In the pruritic patients mast cells were only slightly more numerous than in nonpruritic subjects, although in the patients suffering from pruritus the percentage of tryptase-positive chymase-positive mast cells was significantly decreased compared to nonpruritic individuals. This can play an important role in the etiopathogenesis of pruritus in patients on maintenance haemodialysis treatment.

Keywords: uremic pruritus, haemodialysis, Mast Cells