Uremic pruritus – a review

Abstract

Uremic pruritus remains a frequent concern for hemodialysis patients with the most frustrating and disabling symptoms. The word uremic may denote that patients suffer from acute renal injury. Hence it is preferred to use the recent term “chronic kidney disease associated pruritus” (CKD- associated pruritus). The prevalence of CKD-associated pruritus in patients ranges from 15%-90% in various studies. Interestingly, in CKD associated pruritus the skin lesions are not found. The various skin lesions which range from excoriations, impetigo, linear crusts, papules and ulcers are secondary. Other co-existing diseases like cardiovascular diseases, diabetes, hypothyroidism, chronic liver or hematological diseases may challenge the diagnosis and management. The pathophysiology remains unexplained. There may be an imbalance between the antagonistic activities of µ- and] κ-opioid receptors. Itch sensation are correlated with the activation of certain areas in the brain, spatial and temporal aspects may be processed in the primary somatosensory cortex, planning of scratch response in the pre-motor and supplementary motor cortices, and affective and motivational aspects in the anterior cingulate cortex. A number of different mechanisms have been proposed like xerosis, transdermal water loss, accumulation of pruritogenic substances, increase in parathyroid hormone levels, high levels of urea, calcium, phosphate, β-2 microglobulin but none are convincing. Because of the poorly understood patho-physiological mechanisms the treatment of this condition, have been largely empirical. Reduced hydration may be alleviated by simple emollient therapy. Antihistamines have been widely prescribed in spite of lack of best evidence. UVB phototherapy helps many patients. Anti convulsant, gabapentin may have beneficial effect. Other ole remedies include fish oil, omega 3 fatty acids, IV heparin, thalidomide, lidocaine and mexitine. Recent studies demonstrated that nalfurafine as a systemic agent for two weeks would benefit most patients. All these treatment modalities are best only in addition to the dialysis related treatment like renal dialysis, erythropoietin and renal transplantation.