Correlating pemphigus disease area index (PDAI) severity categories with oral disease severity score (ODSS) in oral mucosal pemphigus - A pilot study

Background Pemphigus vulgaris is a chronic autoimmune blistering disorder that primarily affects the oral mucosa, with over two-thirds of patients developing oral lesions, often preceding skin involvement by weeks or months. The Oral Disease Severity Score (ODSS) provides a detailed, region-specific assessment of oral lesions, facilitating regular monitoring and treatment response. However, it lacks a comprehensive severity evaluation cut-offs needed for systemic therapy decisions. Aim To categorise oral pemphigus severity into moderate, significant, and extensive using ODSS. Methods The study included 25 oral pemphigus patients, confirmed histopathologically or by anti-DSG 3, evaluated severity using ODSS and PDAI scales, with statistical significance analysed between the scores and categories. Results The study comprised 25 subjects with a mean age of 47.48 years (±15.692), including 8 males (32%) and 17 (68%) females. The mean ODSS and PDAI scores were 30.12 (±13.902) and 20.72 (±14.105), respectively. A highly significant positive correlation (r=0.962, p-value <0.001) was observed between PDAI and ODSS scores. An AUC value (>0.8) confirmed ODSS's good discriminating ability, categorising oral pemphigus severity: <21.5 as moderate, 21.5-48.5 as significant, and >48.5 as extensive, per PDAI criteria. Limitation Small sample size is the major limitation of this study. Conclusion This study proposes severity categories for ODSS for oral pemphigus, allowing it to be used for personalised treatment decisions.