Uremic pruritus pathogenesis, revisited.

INTRODUCTION: Uremia is the most important systemic cause of pruritus. Uremic pruritus (UP) was found to affect 50-90% of patients undergoing dialysis and about 25% of patients with chronic kidney disease (CKD). Despite its high prevalence, morbidity and the marked influence on quality of life, UP remains poorly characterized.

REVIEW: Triggering factors for UP may include cutaneous xerosis, uremic toxins, systemic inflammation and associated common co-morbidities such as diabetes mellitus, endocrinopathies,viral hepatitis and somatic neuropathy. Moreover, high pre-dialysis levels of blood urea nitrogen (BUN), β2-microglobulin, calcium and phosphate, as well as parathyroid hormone (PTH) were found to be related to UP. A new hypothesis of glycation, with advanced glycation end products (AGEs) accumulation in stratum corneum has been proposed as a possible underlying cause of UP. Common treatments used for UP include antihistamines, steroids, emollients, charcoal, erythropoietin and phototherapy (UVB). Other treatments with some reported efficacy are serotonin antagonists, selective serotonin reuptake inhibitors (SSRI), mast cell stabilizers, leukotriene receptor antagonists, κ-opioid agonists and nicotinamide. Many non-pharmacological treatments, including acupressure, are also used. In addition, improvement of dialysis modalities could relieve patients of UP. The future use of anti-glycation preparations for treatment of UP is supported by recent researches.

CONCLUSION: Recent researches on the process of glycation as a possible cause of UP may open the way for treatment with anti-glycation preparations. Nevertheless, associated co-morbidities with possible role should be concurrently treated.