Linear immunoglobulin A/G bullous dermatosis associated with ulcerative colitis

Linear immunoglobulin (Ig)A/G bullous dermatosis (LAGBD) is an autoimmune bullous disease characterized by formation of subepidermal blisters and linear deposition of IgA and IgG antibodies along the basement membrane zone (BMZ). The association between linear IgA bullous dermatosis and ulcerative colitis (UC) is well recognized, but reports of UC-associated LAGBD are lacking. We have reported a 24-year-old man suffering from LAGBD associated with UC, which occurred before exacerbations of skin rash. A skin biopsy indicated a subepidermal blister with an infiltration of primarily neutrophils and eosinophils in the dermis. Direct immunofluorescence (IF) studies showed a linear deposition of IgA, IgG and C3c. Indirect IF of human skin revealed IgA and IgG anti-BMZ autoantibodies. Indirect IF of 1 M NaCl-split human skin demonstrated reactivity of IgA and IgG antibodies at the epidermal side. Immunoblotting showed that IgG antibodies reacted to the BP180 NC16a domain and 120-kDa linear IgA dermatosis-1, and enzyme-linked immunoassay detected IgG anti-BP230 antibodies. Administration of prednisolone and diaminodiphenyl sulfone (DDS) via the p.o. route improved skin lesions and bowel conditions. These results suggest that the bowel inflammation observed in UC may have a causative effect of initiation of the immune response to the skin and development of the bullous skin lesions in LAGBD. A combination of DDS and corticosteroid could be a recommended therapeutic option for patients with LAGBD with UC.