[Autoimmune bullous skin disorders]

Abstract

Autoimmune bullous skin disorders are rare, potentially fatal disorders of skin and mucous membranes which are associated with IgG or IgA autoantibodies against distinct adhesion molecules of the epidermis and dermal epidermal basement membrane zone, respectively. These autoantibodies lead to a loss of skin adhesion which shows up clinically as the formation of blisters or erosions. In pemphigus, loss of adhesion occurs within the epidermis while in the pemphigoids, linear IgA dermatosis, epidermolysis bullosa acquisita and dermatitis herpetiformis, loss of adhesion takes place within or underneath the basement membrane zone. The autoantigens of these disorders are largely identified and characterized. Making the diagnosis of autoimmune bullous skin diseases is based on histology and direct immunofluorescence of perilesional skin and the serological detection of autoantibodides by indirect immunofluorescence and recombinant autoantigens. Therapeutically, systemic treatment with glucocorticoids is combined with immunosuppressive adjuvants which allow for the fast reduction of systemic steroids. A prospective trial in pemphigus showed that adjuvant treatment with azathioprine, mycophenolate mofetil and cyclophosphamide, respectively, led to a significant reduction of the cummulative dose of systemic steroids until complete clinical remission was achieved. In bullous pemphigoid, topical treatment with clobetasol led to complete clinical remissions without major side effects seen when glucocorticoids were applied systemically. Therapeutic depletion of B cells by rituximab as a second line therapy has significantly improved the overall prognosis of pemphigus. Comparable controlled therapeutic trials have not yet been performed in dermatitis herpetiformis and epidermolysis bullosa acquisita.