Site-Specific Treatment and Remission Patterns in Multisite Mucous Membrane Pemphigoid

Importance: Mucous membrane pemphigoid (MMP) is a chronic autoimmune blistering disease associated with progressive mucosal scarring and substantial morbidity. Prior studies have often reported remission rates in cohorts combining localized and multisite disease, with limited data on simultaneous remission across all involved sites in patients with multisite disease. Objective: To evaluate multisite complete remission (mCR) and site-specific treatment response patterns in patients with multisite MMP. Design, Setting, and Participants: This retrospective cohort study took place at a single tertiary dermatology and ophthalmology referral center at the University of Texas Southwestern Medical Center between January 1, 2013, and January 1, 2025. Patients with MMP confirmed by immunopathology, disease involving 2 or more anatomic sites, and 12 months posttreatment follow-up were included. Main Outcomes and Measures: The primary outcome was mCR, defined as concurrent complete remission across all involved sites regardless of therapy. Secondary outcomes included site-specific remission and relapse patterns, time to remission, and treatment-associated adverse events. Results: Among 77 patients (55 [71%] female; median [IQR] age at diagnosis, 66 [59-72] years), 68 (88%) had high-risk disease involving ocular, laryngeal, esophageal, or anogenital sites. Oral disease was most common, present in 73 patients (95%), followed by ocular disease in 51 (66%) and nasal disease in 38 (49%). Thirty-five patients (45%) achieved mCR in a median (IQR) of 32.0 (20.7-55.3) months. Although all patients demonstrated improvement and 64 (83%) achieved CR at 1 or more sites, persistent oral and ocular diseases frequently prevented mCR. Relapses following site-level CR occurred in 28 of the 64 patients (44%), most frequently at the oral (18 of 28 patients [64%]) and ocular mucosa (14 of 28 patients [50%]); some patients experienced relapse at multiple sites. Rituximab-based regimens and Janus kinase inhibitor therapy were associated with high rates of improvement. Serious adverse events occurred most frequently with cyclophosphamide monotherapy and Janus kinase inhibitor therapy. Conclusions and Relevance: In this cohort study, fewer than half of patients with multisite MMP achieved simultaneous multisite remission despite high rates of site-level response. Persistent oral and ocular diseases disproportionately limited global disease control, supporting a site-specific model of disease behavior and highlighting the need for standardized multisite remission outcomes in future studies.