Subcutaneous Fat Necrosis of the Newborn Clinical Presentation

Updated: May 15, 2018
  • Author: Sungat K Grewal; Chief Editor: William D James, MD  more...
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Presentation

History

Newborns who develop subcutaneous fat necrosis of the newborn (SFNN) are usually healthy and full-term at delivery, although reports have described children with subcutaneous fat necrosis of the newborn who were born with macrosomia or postterm with normal size. [23] Most have had some antecedent obstetric trauma, meconium aspiration, asphyxia, hypothermia, or peripheral hypoxemia. Congenital ulceration has been reported.

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Physical Examination

Infants with subcutaneous fat necrosis of the newborn (SFNN) usually appear well. The condition begins as an area of edema and progresses to variably circumscribed nodules and plaques that have a deep, indurated feel, implying a panniculitis. The overlying skin may be flesh-colored, red, or purple and may look taut and shiny. The lesions are not warm and are commonly seen on the trunk, arms, buttocks, thighs, or cheeks. Pain may occur, with a frequency as high as 25% in one series. [23] As the lesions progress, they may become fluctuant and spontaneously drain necrotic fat.

See the images below.

Ill-defined erythema overlying an indurated plaque Ill-defined erythema overlying an indurated plaque of a newborn.
Bruiselike indurated plaque of subcutaneous fat ne Bruiselike indurated plaque of subcutaneous fat necrosis of the newborn on the lower back of a newborn.
Ill-defined erythema and induration of subcutaneou Ill-defined erythema and induration of subcutaneous fat necrosis of the newborn on the posterior calf of a newborn.
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Complications

If mild hypercalcemia is present, findings might be absent or the child may display weight loss, irritability, lethargy, anorexia, apathy, constipation, or hypotonia. With severe hypercalcemia, examination may reveal failure to thrive, growth and mental retardation, vomiting, hypertension, seizures, shortening of the QT interval with cardiac arrhythmias, or renal failure. Tissue calcifications, including nephrocalcinosis (calcium deposition in the renal parenchyma), have been reported. [23]  One case of hepatic and atrial myocardial calcification has been reported. [27]

Thrombocytopenia, anemia, hypoglycemia, and hyperlipidemia have also been reported in subcutaneous fat necrosis of the newborn (SFNN) and require close laboratory monitoring. Thrombocytopenia can be a clinical marker of asphyxia and is thought to result from elevated prostaglandin levels in areas of necrosis or increased platelet aggregation in the subcutaneous tissue of affected areas. [7] When inflammation resolves, so does the thrombocytopenia; bleeding problems are rare. [28]

Because perinatal stress associated with gestational diabetes increases infant susceptibility to subcutaneous fat necrosis of the newborn, it is unclear whether hypoglycemia in some subcutaneous fat necrosis of the newborn patients is a complication of subcutaneous fat necrosis of the newborn itself or due to elevated levels of insulin that result from gestational diabetes. [28] Hypertriglyceridemia is postulated to be a result of very low-density lipoprotein cholesterol release from necrotic fat; the triglycerides can be visualized as crystals in the cytoplasm of necrotic adipocytes. [28]

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