Clinicopathological Features of Lupus Erythematosus Panniculitis (LEP): A Retrospective Analysis of 54 Cases

ABSTRACT Background Lupus Erythematosus Panniculitis (LEP) is a rare subtype of Cutaneous Lupus Erythematosus. It is a challenging disease to diagnose and treat due to limited understanding of its clinical and histopathological characteristics. Methods We conducted a retrospective review of 54 biopsy‐proven LEP cases evaluated at a dermatology referral center from 2016 to 2022. Demographic, clinical, laboratory, and treatment data were extracted from medical records, and histopathologic features were reassessed when slides required further characterization. Direct immunofluorescence and serologic results were recorded when available. Statistical analyses were performed using SPSS (v26), with significance defined as p < 0.05. Results Fifty‐four patients with LEP (female‐to‐male ratio 5:1; mean age 38.8 ± 14.7 years) were included. Coexistent systemic lupus erythematosus (SLE) was present in 24.1% of cases. Delayed diagnosis was significantly associated with lipoatrophy ( p < 0.001). Histopathologic findings most commonly included lymphocytic vasculitis (72.2%), histologic features of discoid lupus erythematosus (68.5%), and lobular panniculitis (63%). ANA, anti‐double‐stranded DNA, and direct immunofluorescence were positive in 24.1%, 16.6%, and 72.2% of patients, respectively. Overall, 85.2% of patients improved clinically. Hydroxychloroquine combined with corticosteroids and mycophenolate mofetil was associated with the highest improvement rates, whereas intralesional corticosteroid therapy appeared least effective, although differences were not statistically significant. Conclusion It is essential to evaluate the clinical and histopathologic features of patients accurately before diagnosis. Delay in diagnosis may be more common in patients without associated SLE or DLE, although these associations were not statistically significant in our cohort. Hydroxychloroquine‐based combination therapy, particularly with corticosteroids and mycophenolate mofetil, was associated with favorable clinical outcomes, although prospective studies are needed to establish optimal treatment strategies.