Phototherapy of acne vulgaris with visible light

Background: Sun exposure has a beneficial effect on acne vulgaris, but it is not clear which wavelengths contribute to the favourable effect. Objective: The aim of the study was to investigate the effect of visible light on acne vulgaris and define the most effective wavelengths. Methods: Thirty patients (15 men and 15 women) with mild to moderate acne vulgaris, involving the face and/or the back and/or the chest, were treated with three different light sources. They were treated 3 times a week, for a total of 7 weeks, each field for 20 min per session. Results: All the light sources using 'full spectrum', green and violet improved the acne, leading to 14% (p>0.10), 22% (p<0.05) and 30% (p<0.02) improvement, respectively. No statistically significant differences between the three different light sources were found, although there was a tendency that violet light was better than the other light qualities. No side-effects were observed. Conclusion: Visible light is a moderately effective alternative for treatment of acne vulgaris.