What are the common dermatologic manifestations of kidney disease?
Xerosis or dryness of the skin, especially on the extensor surfaces of the extremities, is common among patients receiving dialysis. It can lead to generalized pruritus and can be uncomfortable.
Changes in pigmentation —in particular, hyperpigmentation—have been attributed to the increased levels of melanocyte-stimulating hormone and the subsequent deposition of melanin in the basal layer of the epidermis.
Some patients may have a “sallow” discoloration of the skin believed to be caused by deposition of lipochrome pigment and carotenoids in the dermis and subcutaneous tissues.
Pallor is commonly associated with varying degrees of anemia as a result of chronic kidney disease.
Uremic frost refers to the deposition of crystallized urea that is excreted from sweat in the epidermis, seen in cases of untreated and advanced kidney disease.
Ecchymoses are commonly associated with uremic platelet dysfunction.
Lindsay nails , also known as “half and half nails,” refer to the whitish discoloration of the proximal half of fingernails, believed to be a result of edema of the nail bed and underlying capillary network.
Acquired perforating dermatosis (Kyrle disease) is predominantly seen in African Americans with diabetes mellitus. It is usually characterized by a linear confluence of papules with a central, oyster shell–like keratotic plug, distributed on the trunk, proximal extremities, scalp, and face, and the lesions are pruritic. Possible etiologies include an inflammatory skin reaction secondary to the presence of uremic toxins, uric-acid deposits, or scratching-induced trauma.
Porphyria cutanea tarda (PCT) commonly presents as a vesiculobullous disease commonly involving the dorsum of both hands and feet but can affect any sun-exposed areas. It is commonly accompanied by sclerodermoid plaques (facial hyperpigmentation) and hypertrichosis. It is usually secondary to increased levels of uroporphyrins.
Avoidance of sun exposure is the cornerstone of management. Other measures to decrease uroporphyrin levels include the use of high-flux dialysis membranes (to improve dialysis efficacy) and small-volume weekly phlebotomies in extreme, rare cases.
Common precipitating factors are alcohol intake, use of estrogen and iron supplementations, and chronic infections (e.g., hepatitis B or C virus, human immunodeficiency virus).
One common differential diagnosis is pseudoporphyria, which is clinically similar to PCT with the exception of normal uroporphyrin levels.
