Bullous Systemic Lupus Erythematosus in a Southeast Asian Cohort: High Systemic Association Driving Systemic Therapy

Bullous systemic lupus erythematosus (BSLE) is a rare autoimmune blistering disorder occurring in association with systemic lupus erythematosus (SLE). Owing to its rarity, current knowledge remains limited, particularly in Southeast Asian populations.

This study retrospectively evaluated the clinical, histopathologic, immunofluorescence, and serologic features of BSLE, together with a review of the existing literature.

This review included patients diagnosed with BSLE at Siriraj Hospital, Mahidol University, between 2003 and 2024.

Among 9,055 patients with cutaneous lupus erythematosus, 12 were identified as having BSLE (incidence 0.13%). The median age was 39.5 years with equal sex distribution. Most patients (75%) presented with BSLE at the time of SLE diagnosis, while others developed it later. Lesions appeared on sun-exposed and non-sun-exposed areas, mainly the extremities, and mucosal involvement occurred in 33.3%. Direct immunofluorescence most frequently demonstrated immunoglobulin (Ig) G deposition (91.7%), followed by complement 3 (83.3%), IgM (75%), and IgA (50%), typically with linear and/or granular deposition of IgG and C3 along the basement membrane zone. Antinuclear antibodies were present in all patients. Systemic involvement was common (75%), most frequently affecting the kidneys (66.7%), followed by hematologic abnormalities (58.3%). Owing to disease severity, most patients required treatment with systemic corticosteroids in combination with immunosuppressive agents rather than dapsone alone to achieve disease control.

This study and literature review highlight that, although BSLE is an uncommon cutaneous manifestation of SLE, it is strongly associated with systemic involvement, particularly renal and hematologic disease, which often necessitates treatment with immunosuppressive agents.