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.

Prospective Randomized Long-Term Study on the Efficacy and Safety of UV-Free Blue Light for Treating Mild Psoriasis Vulgaris.

BACKGROUND: Blue light irradiation reduces the proliferation of keratinocytes and modulates T-cell immune response in vitro and has been shown to reduce the severity of psoriasis vulgaris (Pv) in two clinical trials. OBJECTIVE: Evaluation of safety and efficacy of long-term UV-free blue light treatment at home for mild Pv. METHODS: Forty-seven patients with mild Pv were randomized for receiving high-intensity blue light treatment (HI: 453 nm LED, 200 mW/cm(2), n = 24) and low-intensity treatment (LI: 453 nm LED, 100 mW/cm(2), n = 23) of one Pv plaque for 12 weeks. A contralateral control plaque remained untreated. RESULTS: Patient compliance and satisfaction were high. The primary endpoint, change from baseline (CfB) of the Local Psoriasis Severity Index, revealed a significant improvement of the target compared to the control plaques (ΔCfB for the HI group: -0.92 ± 1.10, p = 0.0005; for the LI group: -0.74 ± 1.18, p = 0.0064). CONCLUSION: UV-free blue light home treatment is safe and improves Pv plaques.

Mechanism and biological relevance of blue-light (420-453 nm)-induced nonenzymatic nitric oxide generation from photolabile nitric oxide derivates in human skin in vitro and in vivo.

Human skin contains photolabile nitric oxide (NO) derivates such as nitrite and S-nitrosothiols, which upon UVA radiation decompose under high-output NO formation and exert NO-specific biological responses such as increased local blood flow or reduced blood pressure. To avoid the injurious effects of UVA radiation, we here investigated the mechanism and biological relevance of blue-light (420-453 nm)-induced nonenzymatic NO generation from photolabile nitric oxide derivates in human skin in vitro and in vivo. As quantified by chemiluminescence detection (CLD), at physiological pH blue light at 420 or 453 nm induced a significant NO formation from S-nitrosoalbumin and also from aqueous nitrite solutions by a to-date not entirely identified Cu(1+)-dependent mechanism. As detected by electron paramagnetic resonance spectrometry in vitro with human skin specimens, blue light irradiation significantly increased the intradermal levels of free NO. As detected by CLD in vivo in healthy volunteers, irradiation of human skin with blue light induced a significant emanation of NO from the irradiated skin area as well as a significant translocation of NO from the skin surface into the underlying tissue. In parallel, blue light irradiation caused a rapid and significant rise in local cutaneous blood flow as detected noninvasively by using micro-light-guide spectrophotometry. Irradiation of human skin with moderate doses of blue light caused a significant increase in enzyme-independent cutaneous NO formation as well as NO-dependent local biological responses, i.e., increased blood flow. The effects were attributed to blue-light-induced release of NO from cutaneous photolabile NO derivates. Thus, in contrast to UVA, blue-light-induced NO generation might be therapeutically used in the treatment of systemic and local hemodynamic disorders that are based on impaired physiological NO production or bioavailability.