A Multicenter Analysis of Patients with Bullous Pemphigoid: Clinical Characteristics and Insights into Drug-Associated Disease

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease, predominantly affecting elderly patients with multiple comorbidities. This multicentre retrospective cohort study aimed to characterize the clinical profile, treatment patterns, and drug-associated cases of BP in a real-world setting. The study included 156 patients newly diagnosed with BP between 2020 and 2024 in four dermatology departments in Poland. Diagnosis was based on clinical features, and immunological assessment, including direct immunofluorescence (DIF), ELISA, and BIOCHIP-based indirect immunofluorescence. The mean age at diagnosis was 75.5 ± 10.9 years, and 78.85% of patients had at least one comorbidity, most commonly arterial hypertension, type 2 diabetes mellitus, and dyslipidemia. Severe pruritus was reported in 74.14% of evaluated patients. Blisters and erosions were the predominant clinical manifestations. Topical glucocorticosteroids were the most frequently used treatment, followed by systemic glucocorticosteroids and methotrexate. New drug exposure within 6 months before disease onset was identified in 14.74% of patients and was associated with a shorter time to diagnosis. Drug-associated cases showed lower BP180 ELISA positivity, although this did not remain significant after correction for multiple testing. These findings highlight the clinical complexity of BP and the importance of medication review and direct immunofluorescence in diagnostic evaluation.