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

Objective: The objective of this study was to assess the prevalence and characteristics of, and knowledge about, photosensitivity and the use of photoprotective measures in an international cohort of cutaneous lupus erythematosus and SLE patients. Methods: We conducted an international, cross-sectional study based on a 46-question web-based survey, including patients with medically confirmed lupus erythematosus, conducted between November 2021 and April 2022. Results: A total of 600 patients with lupus erythematosus [94% female, median age: 41 years, interquartile range (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 [odds ratio (OR) ¼ 3.8; 95% CI 2.5–5.7; P < 0.001] and differed according to the area of residence 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 ultraviolet radiation 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 characterizes lupus erythematosus patients. Photosensitivity frequently includes subjective features, which makes it difficult to evaluate in clinical practice. As fatigue is frequent in lupus erythematosus, further study is needed to clarify the causal link with ultraviolet radiation 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.