Subcutaneous fat necrosis of the newborn: A retrospective study of 32 infants and care algorithm.

Objective: To describe the clinical and laboratory outcomes of infants with subcutaneous fat necrosis of the newborn (SCFN) and propose a care algorithm.
Methods: This single-center, retrospective study of infants diagnosed with SCFN at Ann & Robert H. Lurie Children's Hospital of Chicago from 2009 to 2019.
Results: Of 32 infants who met inclusion criteria, most were born full-term (84%), born via cesarean section (58%), had normal weight for gestational age (69%), and experienced delivery complications (53%). Twenty-nine infants (91%) had calcium drawn, and all had hypercalcemia. Three infants developed clinical symptoms of hypercalcemia, two required hospital admission, two developed nephrocalcinosis, and one developed acute kidney injury. The majority of infants (62%) had a peak ionized calcium between 1.5 and 1.6 mmol/L. No infants with peak ionized calcium less than 1.5 mmol/L developed complications of hypercalcemia. Most patients were diagnosed with hypercalcemia (86%) and demonstrated peak ionized calcium levels (59%) within the first 28 days of life. No patients developed hypercalcemia after 3 months of age.
Conclusion: Hypercalcemia occurred in 100% of infants who had laboratory monitoring. We recommend obtaining an initial ionized calcium level when SCFN is suspected, and monitoring for the first 3 months of life if hypercalcemia has not been detected. In patients with asymptomatic hypercalcemia less than 1.5 mmol/L, there appears to be low likelihood of related complications. For symptomatic, markedly elevated (>1.6 mmol/L), or persistently elevated levels (>6 months) we suggest coordinated care with endocrinology or nephrology, consider hospitalization, and urinary system ultrasound.
(© 2022 The Authors. Pediatric Dermatology published by Wiley Periodicals LLC.)