Table 1. Conditions that can lead to CKDaP.

CKD - Chronic Kidney Disease, CKD-aP - Chronic kidney disease associated pruritus, PTH - Parathyroid Hormone, G3a - Stage 3a of CKD, G5d - Stage 5d of CKD

Etiology	Mechanism	Clinical Features	Treatment
Uremic Toxins	Increase of urea leads to its deposition in the dermis and excretion via sweat, causing pruritus [62].	CKD-aP is itching directly related to kidney disease, its severity and distribution may vary from hardly appreciable, to incessant and disturbing [63].	Treatments can be divided into histamine receptor antagonists and mast cell stabilizers [63]
Dermal Xerosis and Uremic Frost	Causing a disruption of dermal sweat and sebaceous glands, an alteration in skin pH, a reduction in skin lipids, and an overall decrease in skin moisture content [64].	Xerosis manifests as dry, scaly skin [63].	Emollients are mainly used to treat xerosis. There are no randomized control trials to suggest which emollient is best [63].
CKD-associated Mineral Bone Disease	High levels of bone turnover, cause pseudohypoparathyroidism and elevated levels of serum phosphate, which combines with calcium, leading to the deposition of calcium phosphate salts in the skin dermis. This irritates the dermal nerve endings, leading to abnormal firing of neurons and itching [65].	Manifests as one or a combination of the following: 1. Calcium, phosphorus, PTH, or vitamin D metabolism. 2. Bone mineralization, volume, linear growth, or strength. 3. Vascular or other soft tissue calcification [66]	Prevention of hyperphosphatemia in patients with CKD stage G3a to G5D may be more important than treatment or normalization of phosphate levels; it includes dietary restriction of phosphate, use of phosphate lowering agents, and dialysis for patients with CKD stage G5D [66].