Uremic pruritus.

Uremic pruritus and its treatment are reviewed. Pruritus affects 50-90% of patients undergoing peritoneal dialysis or hemodialysis; symptoms usually begin about six months after the start of dialysis and range from localized and mild to generalized and severe. The mechanism underlying uremic pruritus is poorly understood; possibilities include secondary hyperparathyroidism and divalent-ion abnormalities; histamine, allergic sensitization, and proliferation of skin mast cells; hypervitaminosis A; iron-deficiency anemia; neuropathy and neurologic changes; or some combination of these. The cornerstone of therapy for uremic pruritus is regular, intensive, efficient dialysis. Other nonpharmacologic measures consist of the use of non-complement-activating dialysis membranes, compliance with dietary restrictions, electric-needle (acupuncture) therapy, and ultraviolet light therapy. Pharmacologic treatments that have been used include activated charcoal, antihistamines, capsaicin, cholestyramine, emollients and topical corticosteroids, epoetin, pizotyline, ketotifen, and nicergoline. Treatment results have been highly variable, and many of the clinical trials have been flawed. Phosphate-binding agents appear to be the most effective. Although enough is known to determine a reasonable set of steps in approaching a patient's uremic pruritus, more research is needed to understand the pathophysiology of this condition and to establish more reliable treatments. Pruritus is a common and sometimes severe complication of chronic renal failure. Efficient dialysis, dietary restrictions, phosphate-binding therapy, and phototherapy are the most effective treatments currently available.