We report the case of a 59-year-old Japanese woman who developed linear IgA bullous dermatosis during treatment for ulcerative colitis that manifested as pruritic vesicles with erythema on the trunk and scalp. Histopathological examination revealed subepidermal bulla with neutrophil and eosinophil infiltration in the upper dermis. Direct immunofluorescence revealed linear IgA deposits at the basement membrane zone, and indirect immunofluorescence using split skin revealed IgA reaction to the epidermal side (lamina lucida type). We reviewed 33 reported cases of linear IgA bullous dermatosis associated with ulcerative colitis and found that ulcerative colitis preceded the onset of linear IgA bullous dermatosis in 94% of the patients and that IgA-positive patients in split skin indirect immunofluorescence all showed the lamina lucida type, indicating that target antigens for serum IgA antibodies may reside in the lamina lucida. Regarding the pathogenetic association of ulcerative colitis and linear IgA bullous dermatosis, intestinal inflammation may induce the exposure and presentation of intestinal antigens that are cross-reactive to cutaneous antigens, stimulating autoimmune response to antigens of cutaneous basement membrane zones.
Keywords: antigen; basement membrane zone; lamina lucida; linear IgA bullous dermatosis; ulcerative colitis.
© 2019 The Australasian College of Dermatologists.