Over the years many amazing cases have been presented during the PEMPix presentation at the American Academy of Pediatrics’ annual national Conference and Exhibition during the Section on Emergency Medicine Sessions. PEMPix Classic is a new featured series on PEMBlog that will highlight some of those classic cases.

The Case

A three-week old baby presents to the Emergency Department was a rash on his back. History is notable for a cesearan section for failure to progress, post-delivery distress because of suspected meconium aspiration and a brief special care nursery stay.

At one and a half weeks of life he developed a rash on his right shoulder. Subsequently in spread to his entire back and the posterior thighs. He fusses when the rash is touched. Otherwise he has been thriving, feeding well and afebrile.

The only abnormal finding on exam is the rash. It is not warm, and there is no discharge. It is bumpy and nodular to the touch, and he is indeed a little fussy when you palpate the rash, but calms easily.

What is the diagnosis?

A. Sclerema Neonatorum
B. Granulomatous Dermatitis
C. Subcutaneous Fat Necrosis
D. Infantile Myofibromatosis
E. Mongolian Spot

C. Subcutaneous fat necrosis

Though it looks like a Mongolian Spot this rash is bumpy, and the infant fusses. It is also distributed across the entire back and legs – beyond the back and buttocks is not a typical location for Mongolian spots. Subcutaneous fat necrosis in the newborn is seen in areas of trauma following delivery (forceps) or after a stressful delivery – which this infant had. This is a panniculitis (itis = inflammation = fussy)with typically reddish brown subcutaneous nodules and indurated plaques. The can be seen on the back, legs, cheeks and buttocks and almost always develop in the first few weeks of life

The main complication is hypercalcemia, which can be significant and last for 6 months. It is thought to be due to hardening and hyper calcification in the inflamed fat. Perhaps a thirds of infants may have it. and if an infant with subcutaneous fat necrosis has extensive lesions and/or is fussy you should check a serum calcium or ionized calcium. The lesions of subcutaneous fat necrosis will generally resolve in int first several weeks of life, usually by 6-months. Unless hyeprcalcemia is present there is no specific treatment. 

Sclerema neonatorum is a diffuse hardening and seen in critically ill and very low birth weight infants – not our patient. Granulomatous dermatitis is characterized by ring like lesions. Infantile myofibromatosis is the most common fibrous tumor in infancy, and most often (though not always) seen as a single nodular lesion.

References

Burden et al. Subcutaneous fat necrosis of the newborn: a review of 11 cases. Pediatr Dermatol. 1999;16(5):384. 

Del Pozzo-Magaña et al. Subcutaneous Fat Necrosis of the Newborn: A 20-Year Retrospective Study. Pediatr Dermatol. 2016;33(6):e353. 

Mathes et al. UpToDate: Skin nodules in newborns and infants. Accessed 8-23-2019. https://www.uptodate.com/contents/skin-nodules-in-newborns-and-infants/print?search=infantile%20myofibromatosis&source=search_result&selectedTitle=1~4&usage_type=default&display_rank=1