[Uremic pruritus--pathogenesis and treatment].

BACKGROUND: Itching commonly occurs in patients with chronic renal failure, and can be a most distressful and sometimes disabling symptom.

METHOD: This article is based on literature identified through a Pubmed search, textbooks and own clinical experience.

RESULTS AND INTERPRETATION: Inflammatory processes seem to be important in the pathogenesis of uremic pruritus; mechanisms for interference from others factors are not fully understood. Several cytokines that may contribute to development of the disease are released during haemodialysis. Optimal quality of the dialysis is important, as well dialysed patients seem to experience less itching. Secondary hyperparathyreoidism should be treated, as it leads to mast cell proliferation and increased calcium phosphate deposition in the skin and may aggravate the disease. High levels of calcium and magnesium in the skin cause mast cell degranulation and liberation of serotonin and histamine. Peripheral neuropathy may affect the perception of pruritus. Xerosis is frequently observed. Short wave UV treatment (UVB) is considered to be the treatment of choice. Treatment with high dose long wave UV (UVA) (20-25 J/cm2 per treatment) may also be successful. Topical treatment of emollients is recommended and capsaicin may be useful for treatment of localized itching. The effect of systemic antihistamines is at best marginal. Gabapentine, opioid receptor antagonists, cholestyramin, active charcoal and thalidomide have all been used in the treatment of uremic pruritus. Of these, gabapentine seems to be favoured mainly due to fewer side effects.