PL1 Subepithelial bullous diseases – topic overview

Abstract

Subepithelial bullous diseases comprise the group of mucocutaneous autoimmune blistering diseases characterized by subepithelial separation and the deposition of immunoglobulin and complement against several antigens along the basement membrane zone (BMZ). This result in spectrum of diseases that affect skin, oral mucosa, and other mucosal membranes and include bullous pemphigoid (BP), mucous membrane (cicatricial) pemphigoid (MMP), linear IgA disease (LAD), and chronic bullous dermatosis of childhood (CBDC). The most common clinical features are oral erosions, desquamative gingivitis and conjunctival fibrosis, as well as skin lesions, predominantly in older female population. The heterogeneity of clinical presentation and diversity of target autoantigens have contributed to difficulties in characterizing this condition immunologically. In addition to the clinical presentation and a subepithelial vesicle or bullae on routine histologic analysis, the diagnosis is based on direct and indirect immunofluorescence studies. The nature of the disease is determined by the target antigens in the epithelium and BMZ such as antigen 180 (BP180), antigen 230 (BP230), laminin 5, and beta 4 integrin. Circulating IgG and IgA antibodies bind to different epitopes of BP180. The use of salt‐split skin substrate enables differentiation between epidermal and dermal ’binders’. Since the antigen and the antibody titer appear to have direct relationships with the disease severity, and a combination of clinical finding and antibody titer provides valuable prognostic data, these investigations should be carried out routinely. Clinicians should recognize clinical spectrum of SBD, the histopathologic and immunopathologic characteristics, the differential diagnosis, the treatment, and the natural history of the disease. Involvement of oral medicine specialists, dermatologists, ophthalmologists, otolaryngologists and gastroenterologists contribute to early diagnosis and will aid in providing SBD patients with the highest quality of care.