LC-OCT for Cutaneous Lupus Erythematosus: Characterization Across Disease Subtypes and Differentiation From Rosacea

Cutaneous lupus erythematosus (CLE) encompasses a heterogeneous group of autoimmune skin manifestations that often overlap clinically with other inflammatory dermatoses, particularly rosacea. While histopathology remains the gold standard, its invasiveness limits routine and longitudinal use. Line-field confocal optical coherence tomography (LC-OCT) is an emerging non-invasive imaging modality capable of providing real-time, near-histological resolution of skin architecture. In this single-center cross-sectional observational study, 45 patients (30 CLE: 16 acute, 5 subacute, 9 chronic; 15 rosacea) underwent LC-OCT imaging of active lesions. Images were independently evaluated using predefined criteria reflecting histopathological features. LC-OCT identified key histopathological correlates of CLE in vivo. Interface dermatitis features (including dermoepidermal junction disruption, basal cell vacuolization and band-like inflammatory infiltrate) were highly prevalent in ACLE and SCLE, while chronic CLE was characterized by epidermal atrophy, hyperkeratosis, fibrosis and adnexal destruction. In contrast, rosacea exhibited a vascular and folliculocentric pattern with frequent peri-adnexal inflammation and Demodex infestation, without interface changes. Interobserver agreement was substantial to excellent for most criteria. In the ACLE versus rosacea comparison, interface dermatitis features like band-like DEJ infiltrate, DEJ disruption, basal vacuolization and apoptotic bodies were associated with ACLE. Conversely, rosacea exhibited a vascular-folliculocentric profile with peri-infundibular infiltrates and Demodex mites. In conclusion, LC-OCT enables non-invasive visualization of disease-specific microarchitectural patterns in CLE, reflecting both inflammatory and chronic remodelling changes. In this pilot study, it shows potential in differentiating CLE from rosacea and may support diagnosis, staging and treatment monitoring in clinical practice. Larger, multicenter studies are required to confirm the role of LC-OCT in the non-invasive diagnosis of CLE.