Anti-p200 Pemphigoid in an Infant Clinically Mimicking Linear IgA Disease.

We report a 10-month-old boy with annular/polycyclic vesicles on his face, neck, trunk, and extremities that clinically and histomorphologically indicated linear IgA disease (LAD)/chronic bullous disease of childhood (CBDC); however, the immunofluorescence findings and serum positivity for anti-laminin β4 antibodies were consistent with anti-p200 pemphigoid. His condition improved with prednisolone but recurred during tapering; remission was achieved following dapsone administration. Anti-p200 pemphigoid often resembles bullous pemphigoid clinically and is characterized similarly by subepidermal bullae with linear IgG antibody reactivity and C3 basement membrane zone (BMZ) localization, but differs in its target antigen.