Photoprotective effects of a broad-spectrum sunscreen in ultraviolet-induced cutaneous lupus erythematosus: A randomized, vehicle-controlled, double-blind study

Objective We sought to assess if the exclusive use of a broad-spectrum sunscreen can prevent skin lesions in patients with different subtypes of cutaneous lupus erythematosus (CLE) induced by ultraviolet (UV) irradiation under standardized conditions. Methods A total of 25 patients with a medical history of photosensitive CLE were included in this monocentric, randomized, vehicle-controlled, double-blind, intraindividual study. The test product and its vehicle were applied 15 minutes before UVA and UVB irradiation of uninvolved skin areas on the upper aspect of the back in a random order, and standardized phototesting was performed daily for 3 consecutive days. Results Characteristic skin lesions were induced by UVA and UVB irradiation in 16 patients with CLE in the untreated area, and 14 patients showed a positive test result in the vehicle-treated area. In contrast, no eruptions compatible with CLE were observed in the sunscreen-treated area in any of the 25 patients. This resulted in significant differences ( P < .001) between UV-irradiated sunscreen-treated versus vehicle-treated areas, and between UV-irradiated sunscreen-treated versus untreated areas. Furthermore, a significant difference ( P < .05) was observed concerning the age of disease onset and the patient history of photosensitivity. Patients who were younger than 40 years at onset of CLE reported photosensitivity significantly more often than patients with a higher age of disease onset. None of the patients showed any adverse events from application of the test product or the vehicle. Limitations Data resulting from standardized experimental phototesting might not be transferable to a clinical setting. Conclusion These results indicate clearly that the use of a highly protective broad-spectrum sunscreen can prevent skin lesions in photosensitive patients with different subtypes of CLE.