Bald area on back of a girl’s scalp

The Case

The parents of a 4-year-old girl are worried about a bald area on the back of her scalp that has been present since birth.

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DERMCASE diagnosis: Aplasia cutis congenita

Aplasia cutis congenita (ACC) is a congenital malformation typically associated with single or multiple ulcers, crusts, and/or scars in the newborn, with or without other cutaneous and extracutaneous findings.¹ The patient presented with the most common variant, in which an isolated hypertrophic scar is noted on or near the vertex of the scalp. In the newborn, the depth may vary with some cases involving epidermis and superficial dermis, although lesions may extend to deeper soft tissue and rarely through bone revealing exposed brain. The defect is usually 1 cm to 3 cm in diameter and may be rounded, elliptical, or stellate. This variant of ACC must be distinguished from a hair collar sign, in which a smooth, hairless, slightly elevated nodule containing a neuronevus or meningeal cells is surrounded by a dense ring of long hair. 

The causes are variable, including genetic, environmental, teratogenic, and vascular factors. A number of familial cases, most commonly the localized vertex lesions, have been reported.²

More: Curious bald spot on a girl's head

The classification system for ACC is based on the number and location of the lesions and the presence or absence of associated malformations (Table)³:

Management

All patients require a careful medical evaluation to exclude associated findings. Imaging studies may be indicated when deeper soft tissue or bony defects are suspected. Surgical repair is important when the meninges and dural sinuses are involved. Localized superficial ulcers usually heal within 2 to 4 weeks with conservative wound care (eg, silver sulfadiazine).

Outcome

The patient’s scar was present at birth, suggesting that the defect healed in utero. Her growth and development were normal; a review of systems was negative; and the physical exam was otherwise normal. Her parents were reassured accordingly.

REFERENCES

1. Rasmussen JE. Diseases of the scalp. Pediatrics Rev. 1985;7(4):109-116.

2. Mahmood F, Tasneem S, Nadeem MM. Aplasia cutis congenita scalp presenting with life threatening hemorrhage: a case report. J Neonatal Surg. 2012;1(1):8.

3. Frieden IJ. Aplasia cutis congenita: a clinical review and proposal for classification. J Am Acad Dermatol. 1986;14(4):646-660.

Dr Sami is a pediatrician at Metropolitan Pediatrics, Arlington, Virginia. Dr Cohen, section editor for Dermcase, is professor of pediatrics and dermatology, Johns Hopkins University School of Medicine, Baltimore, Maryland. The author and section editor have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article. Vignettes are based on real cases that have been modified to focus on key teaching points. Images also may be edited or substituted for teaching purposes.