Chronic Generalized Pruritus
A 57-year-old man presented to the dermatology clinic with a 1-month history of itching of the whole body, malaise, and muscle cramps. He had received a diagnosis of renal insufficiency 1 year earlier but had been lost to follow-up. A physical examination showed diffuse skin hyperpigmentation and scattered excoriations across his body except for an area in the midscapular region. Laboratory studies showed a blood urea nitrogen level of 128 mg per deciliter (46 mmol per liter; reference range, 8 to 20 mg per deciliter [3 to 7 mmol per liter]) and a serum creatinine level of 15.2 mg per deciliter (1344 μmol per liter; reference range, 0.4 to 1.2 mg per deciliter [35 to 106 μmol per liter]). Computed tomography of the abdomen showed atrophy of both kidneys. Chronic generalized pruritus due to chronic kidney disease was diagnosed. In patients with chronic generalized pruritus, a condition with various possible causes, a butterfly-shaped area of the upper back where a patient cannot reach — also known as the acnestis — may be spared the skin changes that occur as a result of frequent scratching or rubbing. In this case, hemodialysis was initiated, and the pruritus and skin changes abated within 2 months.