A Case of Linear IgA Disease: An Immunofluorescent Study Using Confocal Laser Scan Microscopy

A 79‐year‐old Japanese woman presented with erythema and bullae on her trunk and limbs. Histological examination of the skin lesions showed subepidermal bullae and polymorphonuclear leukocyte infiltration into the papillary dermis. A direct immunofluorescent study showed the linear deposition of IgA, but not of IgG or IgM, in the basement membrane zone. Indirect immunofluorescence of the serum using confocal laser scan microscopy showed IgA, but not IgG, reactivity in the basement membrane zone. In double immunostaining experiments, IgA reactivity was also observed on the epidermal side; laminin 5 was detected on the dermal side.