A 5-day old boy presents with an extensive skin defect on the scalp, which had been present at birth (Fig 1). He was born at 38 weeks via caesarean delivery due to pre-eclampsia. The mother, with a history of hypothyroidism, was treated with levothyroxine during pregnancy. No other medications, teratogenic exposures or trauma were reported during pregnancy. On physical examination, the infant is well and alert. On the vertex scalp, there is an 8-cm stellate ulcerated plaque with a central escharlike crust. There is no hair collar sign. The remainder of skin examination is normal. The head circumference is 34.7 cm (25th percentile), length is 49.0 cm (32nd percentile), and weight is 2.84 kg (12th percentile). His neurologic examination is normal. A head ultrasound reveals a focal defect in the continuity of the soft tissue overlying the ulcer with no underlying vascular anomalies. A subsequent magnetic resonance imaging of brain illustrates that the underlying dural tissue is preserved with no evidence of intracranial extension or contusion to suggest trauma. A swab for herpes simplex virus is negative. The physical examination suggests the diagnosis.The physical examination and the absence of other findings confirms the diagnosis is aplasia cutis congenita (ACC) without associated anomalies.ACC is a rare disorder with an estimated incidence of 3 per 10,000 births characterized by a localized absence of skin. (1) This disease is characterized by localized or widespread areas with partial or full thickness absence of skin at birth that occurs most commonly on the scalp. (2) The condition is believed to result from the disrupted development or degeneration of skin in utero and was first described by Cordon in 1767. (3)ACC presents as a well-demarcated defect with an overlying translucent, glistening epithelial membrane. It may also present as a nonmembranous irregular erosion or ulcer with an overlying crust. Occasionally, the defect may heal in utero and present as a scarred plaque with overlying alopecia at birth. (4)(5) The anatomic site is important when predicting underlying bony involvement or neural tube defect, with lesions overlying the scalp and spine at greatest risk. Imaging should be utilized when there is suspicion of underlying bony or neural involvement (eg, hair collar sign, membranous lesion, midline vertex location, size >5 cm and associated vascular lesions such as cutis marmorata telangiectatic congenita). (4)(5) A hair collar sign is a ring of dark coarse hair surrounding focus of absent skin or a scalp nodule and is a marker for possible spinal dysraphism. (6) Frieden classified ACC into 9 groups according to the pattern and location, underlying causes, and presence of other anomalies as outlined in Table 1. (3) The comprehensive Frieden classification scheme is beyond the scope of this discussion.Numerous factors have been considered as possible causes of ACC, including placental infarcts and vascular compromise, genetic factors, teratogenic substances, intrauterine infections, trauma, and imperfect neural tube closure. (4) There is no evidence that maternal levothyroxine is associated with ACC. The differential diagnoses may include trauma during birth, neonatal herpes infection, and epidermolysis bullosa. It is important to carefully examine the patient for any associated anomalies before classifying the group of ACC.Treatment for ACC varies depending on the extent of involvement (3)(4) although conservative treatment using a bland emollient is the most popular regimen. The most common complication is infection. The use of prophylactic oral antibiotics is not recommended, but topical antibiotics are often used. Serious complications include limb contractures, meningitis, and venous sinus thrombosis. In cases where underlying structures are exposed, surgical intervention with skin or bone grafts may be required. Parents should be counselled that healing will take weeks to months and generally leads to a scar with overlying alopecia.The patient was followed by dermatology. Initially, he was treated with topical petrolatum ointment and mupirocin for 10 days followed by plain petrolatum ointment and silicone dressings. Due to a foul-smelling discharge, he received a 10-day course of cephalexin. The lesion completely re-epithelialized by 4 months of age (Fig 2). The patient is growing and developing normally. However, there will be no hair growth at the site of aplasia cutis. Patients generally are able to camouflage the area with surrounding hair or by parting their hair differently so that it covers the patch of alopecia.
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Oct 25, 2024
Paweł Nojek + 5
Open Access