Personalized Biologic Therapy for Refractory Bullous Pemphigoid: Sequential Omalizumab, Dupilumab, and Rituximab.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease that predominantly affects elderly individuals. Systemic corticosteroids remain a mainstay of therapy but are often limited by comorbidities and treatment-related adverse effects. We report a 73-year-old man with refractory BP and multiple comorbidities who underwent sequential biologic therapy with omalizumab, dupilumab, and rituximab. The diagnosis was supported by typical clinical manifestations, subepidermal blistering, markedly elevated anti-BP180 antibody levels, peripheral eosinophilia, and elevated total IgE, although direct immunofluorescence was negative and indirect immunofluorescence was not performed. Omalizumab did not produce an early clinical response within two weeks, but its efficacy could not be fully evaluated because of the short treatment duration. Dupilumab induced the most rapid clinical improvement; however, relapse occurred after treatment discontinuation due to financial constraints. Rituximab was subsequently administered and contributed to sustained disease control and corticosteroid tapering. This case highlights the complexity of individualized biologic selection in refractory BP and suggests that clinical phenotype, serological profile, treatment response, corticosteroid-sparing needs, safety considerations, and economic accessibility should be integrated when developing personalized treatment strategies.