Definition:

Pemphigoid diseases are group of autoimmune blistering disorders of the skin and mucous membranes characterized by autoantibodies directed against structural proteins of the dermal-epidermal junction that clinically can manifest with urticarial lesions, tense blisters, and erosions which may involve the mucous membranes. Diseases in this group include bullous pemphigoid (BP), dermatitis herpetiformis, mucous membrane pemphigoid, linear IgA bullous dermatosis, herpes gestationis, and epidermolysis bullosa acquisita. BP is the most common acquired bullous autoimmune dermatosis disease. It is primarily a disease of the elderly with an equal incidence in men and women. The clinical characteristics are the formation of tense blisters and pruritic urticarial erythema. Histopathologically, subepidermal blister formation associated with eosinophil infiltration is commonly observed in BP. The main autoantigens targeted by BP autoantibodies are hemidesmosomal transmembrane collagen XVII (COL17, also known as BP180/BPAG2) and the intracytoplasmic plakin family protein BP230. Most of these antibodies belong to the immunoglobulin G class. Diagnosis of BP relies on the clinical and histological aspects, but the most reliable clues are given by direct and indirect immunofluorescence. Three types of drugs, with distinct mechanisms of action, are used to treat BP: anti-inflammatory drugs, drugs designed to reduce the production of pathogenic antibodies, and treatments that increase the elimination of pathogenic antibodies from the serum of patients, such as high-dose intravenous immunoglobulin (IVIG) therapy and therapeutic plasma exchange.