DP17 A very rare presentation of linear IgA disease during pregnancy

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Abstract We present a very rare immunobullous dermatosis, linear IgA disease (LAD), that developed during pregnancy, to highlight its clinical features, management and important safety considerations for the neonate. During her first pregnancy, a 32-year-old Japanese woman of 27 weeks’ gestation developed an intensely itchy blistering rash on her limbs, trunk and face without periumbilical predilection. The blisters were tense, clustering in an annular configuration, with subsequent development of blistering and erosions involving the oral and genital mucosae. Medications included a pregnancy multivitamin only. A lesional skin biopsy revealed a subepidermal blister containing neutrophils and eosinophils. Direct immunofluorescence of perilesional skin demonstrated linear deposition of IgA along the basement membrane zone. Linear IgA disease was diagnosed. Initial treatment consisted of erythromycin and daily clobetasol ointment. Owing to inadequate symptom control and blister progression, dapsone 50 mg daily was initiated with prompt improvement in her condition and cessation of new blistering. A postpartum flare necessitated a dose increase to 75 mg daily. Her baby’s glucose-6-phosphate dehydrogenase (G6PD) level was found to be normal at birth. She proceeded to breastfeed her son, and monitoring of his haemoglobin level was normal. Although her clinical presentation initially raised the possibility of pemphigoid gestationis (PG), there was no periumbilical involvement, and the morphology of blistering in conjunction with mucosal involvement was more suggestive of LAD. The immunofluorescence results also helped to distinguish LAD from PG. The new onset of LAD during pregnancy is very unusual and has been rarely reported (Ikkaku N, Tateishi N, Oda Y et al. Linear immunoglobulin A bullous dermatosis developing during late pregnancy. J Dermatol 2017; 44:e44–5). Pre-existing LAD typically improves during pregnancy, although postpartum flares are recognized. Pemphigoid gestationis has been associated with an increased risk of prematurity and intrauterine growth restriction, but this has not been reported with LAD during pregnancy, possibly due to its rarity. Both the diagnosis of LAD and its mainstay treatment—dapsone—have important potential implications for the neonate. As for other immunobullous diseases, transplacental transfer of pathogenic antibodies may result in transient, usually mild, neonatal blistering. Although dapsone can be safely used during pregnancy and breastfeeding, the risk of neonatal haemolysis and methemoglobinaemia necessitates the assessment of the G6PD level and haemoglobin monitoring in the neonate. Multidisciplinary input from the dermatology, obstetric and paediatric teams is crucial to ensure appropriate counselling and care of the affected mother and baby.