Classification of Skin Changes
Acute renal failure
Edema
Uremic frost (deposition of urea crystals on skin surface in severe uremia)
Chronic renal failure
Edema
Uremic frost
Calciphylaxis
Bullous disease of hemodialysis (pseudoporphyria, see Section 23)
Nephrogenic fibrosing dermopathy
Acquired perforating dermatosis
Calciphylaxis ICD-9: 275.49 
ICD-10: E83.59 
Calciphylaxis is characterized by progressive cutaneous necrosis associated with small- and medium-sized vessel calcification and thrombosis.
It occurs in the setting of end-stage renal disease, diabetes mellitus, and secondary hyperparathyroidism. Most often follows initiation of hemo- or peritoneal dialysis.
Precipitating factors: glucocorticosteroids, albumin infusions, IM tobramycin, iron dextran complex, calcium heparinate, vitamin D.
Preinfarctive lesions show mottling or livedo reticularis pattern, dusky red (Fig. 18-1A).
Turn into black, leathery eschar (Fig. 18-1B) and ulcer with tightly adherent black or leathery slough. Ulcers enlarge over weeks to months; when debrided reach down to fascia and beyond; areas of plate-like induration can be palpated surrounding infarcted or ulcerated lesions (Fig. 18-2).
Extremely painful.
Lower extremities, abdomen, buttocks, penis.
Azotemia. Calcium X phosphate ion product usually elevated. Parathormone levels usually but not always elevated. Dermatopathology: calcification of media of small- and medium-sized blood vessels in dermis and subcutaneous tissues.
Slowly progressive, despite therapy. Ulcus become secondarily infected.
Management: treatment of renal failure, partial parathyroidectomy when indicated, debridement of necrotic tissue.
Figure 18-1. Calciphylaxis (A) Early stage. An area of mottled erythema, starburst-like, and reminiscent of livedo reticularis with two small ulcerations. Patient has chronic renal failure and is on hemodialysis. Even at this early stage, lesions are extremely painful. (B) Calciphylaxis, more advanced lesion. An area of jagged necrosis on the lower leg in a patient with diabetes and chronic renal failure who is on hemodialysis. The surrounding skin is indurated and represents a plate-like subcutaneous mass that is appreciated only upon palpation.
Figure 18-2. Calciphylaxis, extensive Lesions are ulcerated, the surrounding skin is indurated, best seen on left thigh where skin is hairless. Similar lesions are also found on the abdomen.
Nephrogenic Fibrosing Dermopathy (NFD) ICD-9: 701.8 ICD-10: L90.8 
NFD is a fibrosing disorder in patients with acute or chronic renal failure.
Most patients receiving hemodialysis, peritoneal dialysis; in acute renal failure, NFD occurs without dialysis.
It is part of a wider spectrum of nephrogenic systemic fibrosis involving the heart, lungs, diaphragm, skeletal muscle, liver, genitourinary tract, and central nervous system.
Etiology unknown but exposure to gadodiamide containing contrast media for MR angiography is a strong association. Gadodiamide is found only in lesions and not in normal tissue. Myofibroblasts and fibrogenic cytokines (e.g., transforming growth factor β) may be involved in the pathogenesis.
NFD is characterized by acute onset, brawny indurations, plaque-like or nodular, bound down upon palpation (Fig. 18-3); up to 20 cm and more in diameter, with an uneven rippled surface.
Mostly on lower extremities, less often on upper extremities and torso but not the face.
Tingling, tender, often painful.
Differential diagnosis: morphea, pretibial myxedema, lipodermatosclerosis, panniculitis.
Course is chronic, unremitting; prognosis guarded.
Therapy unknown. Imatinib may be beneficial
Figure 18-3. Nephrogenic fibrosing dermopathy A brawny plate-like induration bound down upon palpation, with an uneven surface on the legs. This patient had end-stage chronic renal failure and was on hemodialysis.
Acquired Perforating Dermatosis* ICD-9: 709.8 ICD-10: L87.0 
Occurs in chronic renal failure and diabetes mellitus; in up to 10% of patients undergoing hemodialysis.
Chronic pruritic condition triggered by trauma.
Umbilicated papules with central hyperkeratotic crust (Fig. 18-4).
Transepidermal elimination of collagen.
Relationship with other perforating disorders not clear.
*For more detailed information, see Minocha JS and Schlosser BJ: Chapter 69 in Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, and Wolff K (eds.). Fitzpatrick’s Dermatology in General Medicine, 8th ed. New York, McGraw-Hill, 2008:727–731.
Figure 18-4. Acquired perforating dermatosis in a patient undergoing hemodialysis There are purpuric umbilicated papules with a central hyperkeratotic crust.