皮膚科医のための皮膚および全身性ループスの実践的アプローチ：皮膚科マスタークラス2025会議より

Cutaneous lupus erythematosus (CLE) may occur independently or in association with systemic lupus erythematosus (SLE). When systemic disease is present, CLE is the first manifestation in nearly one-third of cases. This positions dermatologists as key stakeholders in early detection of systemic disease, underscoring the importance of appropriate screening among this population. Various CLE subtypes carry distinct risks of systemic progression, with acute CLE closely tied to active SLE, subacute CLE conferring moderate risk, and most chronic subtypes (eg, localized discoid lupus) remaining limited to the skin. This review provides a practical, dermatology-focused framework for risk stratification, screening, and comanagement of patients with CLE. To support clinical decision-making and expand awareness, we introduce the "LABS FOR" SLE mnemonic to guide laboratory evaluation and propose an updated visual algorithm that illustrates screening and monitoring practices. We synthesize evidence-based and expert-informed recommendations, including serologic, demographic, clinical, and genetic predictors of systemic involvement. The 2019 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria-requiring antinuclear antibody (ANA) positivity and weighted domain scoring-are reviewed and compared to other diagnostic aids. Additionally, we highlight appropriate ANA testing, the importance of symptom review, and targeted second-line labs. Finally, we discuss collaborative management strategies with rheumatology, including organ-specific therapeutic considerations. By adopting a structured, CLE-informed approach to systemic screening and follow-up, dermatologists can play a critical role in improving outcomes for patients across the lupus spectrum.