Bullous pemphigoid is the most frequent autoimmune blistering skin disease of the elderly. It is mediated by circulating antibodies directed against two hemidesmosomal proteins of the dermal epidermal junction: BPAG1 and BPAG2. Clinical features consist of pruritus and tense blisters usually surrounded by erythema. Blisters sometimes evolve to erosions, become haemorrhagic or even large erosive areas. Lesions heal without scarring. Lesions are symmetrically located on the thighs, legs, trunck and arms. Mucous membranes are usually uninvolved. Histological examination of a skin biopsy specimen shows a subepidermal blister with eosinophils within the blister and the superficial dermis. Direct immunofluorescence shows linear IgG and/or C3 deposits along the dermal epidermal junction. In France and in Europe, most patients are now treated using topical steroid therapy (clobetasol propionate).
J Dermatol Sci. March 2014. Update on the pathogenesis of bullous pemphigoid: An autoantibody-mediated blistering disease targeting collagen XVII. BP is a common autoimmune blistering skin disorder that tends to affect the elderly. Autoantibodies (autoAbs) from BP patients react with two hemidesmosomal components: transmembrane collagen XVII (BP180 or BPAG2) and plakin family protein BP230 (BPAG1). Of these, collagen XVII (COL17) is thought to be a major autoantigen. The binding of autoAbs to COL17 following the activation of complements and inflammatory pathways eventually leads to the degradation of COL17, and this has been regarded as the main pathogenesis of BP. However, recent investigations have suggested other pathways, including a complement-independent pathway and a pathway involving IgE-autoAbs. BP-autoAbs can directly deplete COL17, leading to fragility of the dermal-epidermal junction. In addition, IgE-autoAbs to COL17 may be involved in the formation of itchy urticarial erythema associated with eosinophilic infiltration.
Cicatricial pemphigoid information and treatment
Cicatricial pemphigoid is an eye disorder. The ocular manifestations of autoimmune bullous diseases are common and potentially sight-threatening. Major ophthalmic involvement is most commonly seen in mucous membrane pemphigoid (cicatricial pemphigoid), epidermolysis bullosa acquisita, linear IgA bullous disease, pemphigus vulgaris and paraneoplastic pemphigus. The main pathological process is related to autoimmune-induced conjunctival inflammation with consequent lid and corneal pathology, which may eventually result in permanent visual loss. Ocular involvement can be asymptomatic. Early detection is aided by careful attention to symptoms and signs of early ophthalmic disease. Ocular disease can be difficult to treat and management usually involves systemic therapy with immunomodulators to control inflammation and prevent progression to irreversible blindness, as well as surgical intervention in advanced disease.