Herpes gestationis (HG) is a rare, autoimmune, bullous disease that occurs during the second or third trimester and usually resolves over weeks or months after delivery. Neonates with HG are rare (estimated at 1 per 100 000 cases). Although anti–180-kDa bullous pemphigoid (BP180) autoantibody and transfer of this autoantibody are known as the cause, to our knowledge, no coordinated analysis of clinical symptoms and anti-BP180 antibody enzyme-linked immunosorbent assay titers has been reported in a mother and neonate with HG.
We describe a 33-year-old woman with HG and her neonate with vesicular erythematous lesions and the weekly follow-up results of the BP180 noncollagenous domain (NC16a) enzyme-linked immunosorbent assay.
Almost the same titer of pathogenic antibody as that in the mother is transferred to the neonate. The plasma elimination half-life of anti-BP180 antibody is approximately 15 days in mother and neonate. An abrupt twin peak increase in the BP180 enzyme-linked immunosorbent assay index from maternal serum was observed just before and after delivery, possibly explaining why HG usually occurs in the last trimester of pregnancy and exacerbates postpartum. Lesions in the neonate resolve without treatment far before pathogenic antibody disappears, suggesting that factors other than anti-BP180 antibodies may be involved in the generation of eruptions. Frequent testing of the BP180 enzyme-linked immunosorbent assay greatly facilitates therapeutic planning.