Prevalence, characteristics, and knowledge related to photosensitivity in patients with lupus erythematosus: the international PHOTOLUP study.

OBJECTIVES: To assess the prevalence, characteristics and knowledge about photosensitivity and the use of photoprotective measures in an international cohort of cutaneous and systemic lupus erythematosus patients. METHODS: We conducted an international, cross-sectional study based on a 46-question web-based survey including patients with medically confirmed LE conducted between November 2021 and April 2022. RESULTS: 600 patients with lupus erythematosus (94% female, median age: 41 years [IQR: 33-51]) from 50 countries were included. A history of photosensitivity was reported by 389/600 (64.8%) patients. Photosensitivity was associated with the presence of other cutaneous involvement (OR = 3.8; 95%CI 2.5-5.7; p < 0.001) and differed according to the area of habits and level of education (p < 0.001, for all). Photosensitivity was characterized by a wide range of clinical manifestations (both cutaneous and systemic symptoms in 56.1% and systemic symptoms only in 29.8% of patients). Fatigue was the most frequently reported systemic manifestation (82.3%). Overall, 559/600 (93%) patients were aware of the detrimental role of UV exposure in lupus erythematosus, but 160/480 (33.3%) were unaware of the importance of photoprotective measures, including 90/310 (29%) among those with photosensitivity. CONCLUSION: A high rate of self-reported photosensitivity characterize lupus erythematosus patients. Photosensitivity frequently includes subjective features, which makes it difficult to evaluate in clinical practice. As fatigue is frequent in LE, further study is needed to clarify its causal link with UV exposure. About one-third of lupus erythematosus patients are unaware of the importance of photoprotective measures. This should be improved through more frequent and targeted awareness interventions.