Blistering diseases

Blistering occurs in many situations - infections (viral and bacteriological), in response to physical or chemical trauma, as a reaction to drugs, and as a result of specific blistering diseases. The autoimmune blistering diseases, the pemphigus and pemphigoid group, are characterized by autoantobodies directed against antigens that are structural proteins forming part of the adhesion complexes of the skin. In pemphigus, autoantibodies are formed against desmogleins, the major component of the desmosomes, and result in superficial, intra-epidermal blistering, manifest as erosions of the skin and mucous membranes. The skin and mucosa differ in relative expression of the two desmogleins involved and the clinical picture correlates with the autoantibody profile. The pemphigoid group (bullous pemphigoid, mucous membrane pemphigoid, pemphigoid gestationis) is characterized by different clinical syndromes, all associated predominantly with autoantibodies to BP180, a large transmembrane protein forming part of the basement membrane zone adhesion complex that links the epithelium to the underlying dermis. The autoantibodies are known to be pathogenic in bullous pemphigoid and pemphigoid gestationis and lead to large, tense, subepidermal blisters. The different clinical syndrome of mucous membrane pemphigoid with erosions and scarring of mucosal surfaces is more difficult to explain. Genetic epidermolysis bullosa is characterized by mutations in skin structural proteins, either the keratinocyte keratins, with splitting through basal epidermal cells, or adhesion complex proteins, with blistering of the basement membrane zone.