Seventy adult patients with linear IgA disease were studied. Five (7.1%) also suffered from ulcerative colitis (the prevalence of ulcerative colitis in the U.K. is 0.05%). A further three patients with this association, from other British centres were also reviewed. In all cases, ulcerative colitis preceded the onset of skin disease, by a median of 6.5 years. The reason for this association remains unclear but the abnormalities in colonic mucosal B cells and mucosal IgA1 production reported in patients with ulcerative colitis may be important in the subsequent development of IgA1 mediated linear IgA disease.