P16 Linear bullous aplasia cutis congenita of the scalp: an unusual presentation of a rare condition

Abstract

Abstract Aplasia cutis congenita (ACC) is a heterogenous group of congenital disorders characterized by focal or widespread absence of skin. Bullous ACC is a rare variant that presents with well-circumscribed oval lesions resembling bullae or vesicles covered with a thin membrane. There have been 20 previously reported cases of bullous ACC. We present a female neonate referred to dermatology at day 2 of life following an IVF-assisted pregnancy and delivery by elective caesarean section for breech presentation. There was no antenatal history of infection, trauma or drugs, and no relevant family history. Clinical examination of the parietal scalp revealed five well-demarcated bullae in a linear distribution along Blaschko lines. The hair collar and ‘golf club set’ signs were absent. Skin swabs for microbiology and viral studies were negative. Ultrasonography showed no associated osseous defect. Clinical examination was otherwise normal. A diagnosis of multibullous ACC was made, and a conservative approach adopted. Clinical follow up at 2 years found resorption of one bulla with flattening of the remainder. Neurodevelopment was normal. On review of the literature, 10/20 (50%) cases of bullous ACC presented with multiple bullae. The hair collar sign was positive in 50%, strengthening theories that bullous ACC may represent a ‘forme fruste’ of a neural tube defect. Four other cases reported distribution along Blashko lines, suggesting possible underlying cutaneous mosaicism. The majority (90%) had no associated cutaneous or extracutaneous findings. Clinical outcomes were good with spontaneous resorption of bullae, suggesting conservative management is appropriate in most cases.