Linear IgA disease of adults, chronic bullous disease of childhood, and the rare childhood cicatricial pemphigoid currently are regarded as separate clinical entities despite their many shared features. All are sulfone-responsive subepidermal bullous diseases associated with linear IgA deposition at the basement membrane zone. In this paper we present a long-term study of 25 cases of adult linear IgA disease, 25 cases of chronic bullous disease of childhood, and four cases of childhood cicatricial pemphigoid, which has revealed further similarities among all three groups. The morphology and distribution of the cutaneous and mucosal lesions were similar; mucosal involvement was present in 80% of patients with adult linear IgA disease, 64% of those with chronic bullous disease of childhood, and 100% of those with childhood cicatricial pemphigoid, and ocular scarring affected patients in all groups. Remission occurred in 64% of those with chronic bullous disease of childhood (the disease was active in 12% after puberty), 48% of those with adult linear IgA disease, and in no cases of childhood cicatricial pemphigoid. HLA B8 and circulating IgA anti-basement membrane zone antibody were more common in chronic bullous disease of childhood than adult linear IgA disease. There were no absolute differences among the three groups, and we suggest that adult linear IgA disease, chronic bullous disease of childhood, and childhood cicatricial pemphigoid are the same disease, with childhood cicatricial pemphigoid being a more severe form of chronic bullous disease of childhood.