Uremic frost

Abstract

A 75-year-old male was admitted with pedal edema and respiratory distress of two weeks and altered sensorium of two days duration. According to his attendants, he was a known case of chronic kidney disease of many years, and not on regular follow-up. On examination, deposits of tiny white crystalline material were observed on his face and feet [Figures 1 and 2]. On investigation the hemoglobin was 7.6 g%, blood urea was 233 mg%, serum creatinine was 12 mg%, and serum potassium was 6.7 meq/l. Arterial blood gas analysis was consistent with metabolic acidosis. A provisional diagnosis of end stage renal disease was considered on clinical grounds, crystalline deposits being uremic frost. Patient was planned for hemodialysis but had a sudden cardiac arrest and died. Figure 1 Uremic frost on forehead Figure 2 Uremic frost on feet Uremic frost was first described by Hirschsprung in 1865. This dermatological disturbance of advanced chronic kidney disease is rarely observed in developed countries, but is still reported from resource poor nations. It occurs when high concentration of urea and other nitrogenous waste products accumulate in sweat and crystallize as deposits on skin after evaporation. The dermatological differential diagnoses are retention keratosis, eczema, and postinflammatory desquamation. However, a history of end-stage renal disease and the white, friable, crystalline characteristics of uremic frost can make its diagnosis easy. To verify that the crystals are composed of urea or nitrogenous waste, scrapings of the frost can be diluted in normal saline, which can then be tested for elevated urea nitrogen levels comparable to blood levels.[1 2]