Supplementary Material for: Prospective, Randomized Study on the Efficacy and Safety of Local UV-Free Blue Light Treatment of Eczema

Background: Blue light was shown to reduce the activation of T cells and modulate cytokine release in vitro. Therefore, we investigated the efficacy of blue light in the treatment of eczema. Methods: A sample of 21 patients with mild to moderate eczema were locally treated with blue LED light (light-emitting diode, emission maximum: 453 nm). They received light treatment 3 times per week for 4 weeks. A contralateral control lesion remained untreated. Results: A total of 20 patients completed the trial with a compliance rate of 100%. The blue light treatment was safe with no adverse events and no side effects. The primary end point change from baseline in the mean sum score of the local Eczema Severity Index (local ESI) was more pronounced for the treated area than for the control area (-1.9 ± 2.02 vs. -1.3 ± 2.24). The treatment difference was statistically significant (p = 0.0152, paired t test, two-sided). Conclusion: In this study UV-free blue light was safe and effective in the reduction of eczema lesions.