International Pemphigus Committee Treatment Guidelines

Overview / Definition Pemphigus encompasses a group of rare, chronic, and potentially life-threatening autoimmune blistering disorders that primarily affect the skin and mucous membranes. The most common subtypes include pemphigus vulgaris and pemphigus foliaceus, which are characterized by the presence of autoantibodies against desmoglein proteins, leading to disruption of cell adhesion and blister formation. Epidemiology Pemphigus is relatively rare, with an estimated incidence of 0.1 to 0.5 cases per 100,000 individuals per year. It predominantly affects adults, with a peak incidence in the fifth to sixth decades of life. Certain populations, particularly those of Mediterranean and Ashkenazi Jewish descent, exhibit a higher prevalence. Pathophysiology / Mechanism The pathophysiology of pemphigus involves an autoimmune response against desmosomal proteins, primarily desmoglein 1 and desmoglein 3. The binding of autoantibodies to these proteins disrupts intercellular adhesion, leading to acantholysis and the formation of intraepithelial blisters. This process is mediated by various immune mechanisms, including complement activation and recruitment of inflammatory cells. Clinical Presentation Patients with pemphigus typically present with painful, flaccid blisters that are prone to rupture, leading to erosions and crusting. Key features include: Pemphigus vulgaris: Characterized by oral mucosal involvement and skin lesions that appear as flaccid blisters. Pemphigus foliaceus: Primarily affects the skin with superficial blisters, typically sparing mucosal surfaces. Other systemic manifestations may occur, including fever, malaise, and weight loss, depending on the extent of disease involvement. Diagnosis / Workup The diagnosis of pemphigus is primarily clinical, supported by histopathological and immunological findings. Key steps in the diagnostic workup include: Clinical evaluation of blistering lesions and mucosal involvement. Histopathology: A skin biopsy reveals