Discoid Lupus Erythematosus: A Comparative Evaluation Between Line‐Field Confocal Optical Coherence Tomography and Histology in a Multicenter Cross‐Sectional Study

Discoid lupus erythematosus (DLE) is the most common variant of cutaneous lupus. Histopathology remains the gold standard for diagnosis, but it carries a risk of scarring in a disease already prone to cicatricial outcomes. Additionally, diagnostic delays may occur due to variable processing times, particularly in challenging cases. Line‐field confocal optical coherence tomography (LC‐OCT) is a novel non‐invasive imaging technique offering high‐resolution, histology‐like features. This study evaluates its diagnostic accuracy in DLE by assessing concordance with histopathology. A cross‐sectional study enrolled histologically confirmed DLE from three tertiary referral hospitals. Eleven histological criteria were assessed using LC‐OCT and subsequently compared to histopathology. Concordance was evaluated using Cohen's Kappa coefficient ( K ), with McNemar's test applied to detect significant differences ( α = 0.05). Twenty‐eight patients with DLE participated in the study. LC‐OCT demonstrated strong agreement with histopathology in key diagnostic features of DLE. Near‐perfect concordance ( K = 1, 100% agreement) was observed for interface dermatitis, dermal vessel dilation, epidermal atrophy, and incontinentia pigmenti. Substantial agreement was found for epidermal disarray ( K = 0.85), spongiosis ( K = 0.70), necrotic keratinocytes ( K = 0.70), and infundibular dilation ( K = 0.79). Overall, LC‐OCT achieved a Cohen's Kappa of 0.74 with 87.66% concordance, and no statistically significant differences were observed between the two methods (McNemar p = 0.627). LC‐OCT is a rapid, effective, and non‐invasive diagnostic tool for DLE, demonstrating strong concordance with histopathology and potential for early diagnosis and clinical implementation.