Atopic Dermatitis: a Short Summary
- Subcutaneous Fat necrosis of the newborn
What is Subcutaneous Fat necrosis of the newborn ?
- It is a lobular panniculitis.
- It is associated with complications during labor (labour)
- It presents as asymptomatic indurated subcutaneous dark-red nodules which are typically located in bone proeminant areas (upper back, proximal limbs, cheeks…)
When does it occur ?
- It occurs between 1 and 5 weeks following delivery.
Why does it happen ?
It is largely unknown but here is a hypothesis:
- Fat in the newborn contains a higher proportion of saturated fat; more exactly palmitate (palimitic acid). Saturated fat has a lower melting point (solid to liquid transition), which means that it crystallizes more easily.
- Because of fetal suffering (which consists of meconium aspiration, preeclampsia, prolonged labor, caesarean section…)…there is injury to the subcutaneous fat tissue which then crystallizes.
How does it evolve ?
- It resolves itself spontaneously within one to 4 months.
- There is no scar.
- Complications are of hypercalcemia which can lead to cardiac, neurological, and/or nephrologic impairement.
What is the differential diagnosis ?
- Diagnosis is usually straightforward but Sclerema Neonatorium must be differentiated. It is a diffuse subcutaneous sclerosis which heals with fibrosis.
- It is considered by some as an extensive form of subcutaneous fat necrosis.
One word on the classification of panniculitis
- Panniculitis is classified into septal, lobular or mixed forms.
- Although not exhaustive here, causes of lobular panniculitis include, lupus panniculitis, infectious panniculitis, erythema induratum of Bazin. Septal causes include erythema nodosum.
Comment: In the French literature, it is entrenched in the mind of some dermatologists that “panniculite” is used for lobular panniculitis.
Source of Information:
Laffitte E. 2012 (09) – 21st Annual Congress of the EADV (European Academy of Dermatology and Venerology) – Prague (Praha), Czech Republic (česká republika)
Dubertret L. Thérapeutique Dermatologique, 2011 Online Edition
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