Subcutaneous fat necrosis of the newborn is a rare condition resulting in firm, inflamed, skin-coloured to purple nodules (lumps) in the fat, It occurs in the first weeks after birth. It is a form of panniculitis.
The nodules may present as discrete lumps on the back, buttocks and limbs, or as large hardened areas. It is less severe than sclerema neonatorum, another condition that may cause hardened skin in a newborn baby.
The exact cause of subcutaneous fat necrosis is not known. A number of factors seem to be more common in affected infants including:
However most babies who are exposed to these factors do not get subcutaneous fat necrosis.
The nodules of subcutaneous fat necrosis may be painful. They may last from weeks to months before they disappear. Occasionally the infant may be left with a dimpled area of reduced fat.
The most common complication of subcutaneous fat necrosis is hypercalcaemia (high blood calcium). This is detected on a blood test, so babies with subcutaneous fat necrosis should have their blood calcium checked periodically for the first few months of life. Hypercalcaemia can cause irritability, constipation, poor weight gain and, very rarely, heart rhythm disturbance.
Thrombocytopenia (low platelets) and hyperlipidaemia (raised levels of fat in the blood) have also been observed.
Treatment of subcutaneous fat necrosis focusses on management of hypercalcaemia, if it occurs. Hypercalcaemia may be treated by increased fluid intake, low calcium milk feeds, frusemide, corticosteroids and bisphosphonates.
The inflammation of the fat often settles without specific treatment.
