Histopathologic Overlap Between Bullous Lupus Erythematosus and Linear IgA Bullous Dermatosis: A Comparative Study

Area of Science:

• Dermatology
• Autoimmune Diseases
• Pathology

Background:

• Bullous lupus erythematosus (BLE) and linear IgA disease (LAD) are rare autoimmune subepidermal blistering diseases.
• These conditions share overlapping clinical and histopathological features despite distinct pathogenetic mechanisms.

Purpose of the Study:

• To compare the histopathologic features of Bullous lupus erythematosus (BLE) and linear IgA disease (LAD).
• To assess the diagnostic utility of histopathology in differentiating these two rare blistering diseases.

Main Methods:

• Retrospective analysis of histopathologic findings in 11 cases of BLE and 11 cases of LAD.
• Evaluation of clinical presentation, epidermal changes, inflammatory infiltrate, and dermal features.

Main Results:

• Subepidermal neutrophil-rich blisters were observed in a majority of both BLE (60%) and LAD (54.54%) cases.
• Eosinophils in blisters were noted in LAD (36.4%) but not BLE cases.
• No statistically significant histopathologic differences were found between BLE and LAD, including epidermal changes, inflammation patterns, and dermal mucin levels.

Conclusions:

• Histopathology alone has limited value in distinguishing Bullous lupus erythematosus from linear IgA disease.
• Diagnosis relies heavily on immunofluorescence and serologic findings, even in clinically suggestive cases.