Light therapy for acne vulgaris

Exposure to natural and artificial ultraviolet (UV) light has been reported to be successful in treating those suffering from acne vulgaris for a number of years⁶. The exact mechanism for the response of the acne lesions to UV light is not fully understood, but felt to be partly owing to the destruction of the P. acnes bacteria in the sebaceous unit, in what can be described as a photodynamic therapy (PDT) mechanism of action. This natural endogenous PDT reaction works well in the treatment of acne vulgaris; however, the damaging effects of UV light with regard to the potential for photoageing and the development of skin cancers limits its regular use in today’s medical environment.

[pull_quote align=”right” ]The first FDA-approved blue light was a high-intensity, narrow-band source with an absorption peak at 417 nm.[/pull_quote]

The photodynamic reaction seen in the destruction of the P. acnes bacteria involves the natural production of porphyrins, seen during the growth of the P. acnes at the inflammatory phase of the acne cycle. The porphyrins produced are principally Protoporphyrin IX (PpIX) and Coproporphyrin III, which have been shown to have absorption spectra in the near UV range of light. This absorption spectrum is in the blue light range, with peak absorption seen at 415 nm. The PDT reaction that occurs works through the photoactivation of the P. acnes porphyrins with exposure to the appropriate light source. This causes the formation of singlet oxygen within the bacteria and selective destruction of the P. acnes bacteria, with destruction of the acne lesion itself, leaving the surrounding tissues and associated structures alone.

A variety of laser and light sources have been used to treat acne vulgaris via P. acnes destruction. In the past these have included halogen, xenon, and tungsten light sources. More recent investigations have predominantly focused on blue and red light. With the addition of a topical photosensitiser applied to the skin prior to light therapy, blue and red light, vascular lasers, and the intense pulsed light (IPL) sources all seem to work even better than the laser or light source alone. Once again, the reader should review the medical literature as to how PDT with photosensitisers can be used to treat
acne vulgaris.

Treatment of acne vulgaris with blue light

In-office blue light sources

Blue light therapy for the treatment of inflammatory acne vulgaris has been reviewed extensively in the medical literature^2,7. There have been three major blue light systems available for the treatment of inflammatory acne and these systems, along with the literature supporting them, will be reviewed. The reader should be aware that other blue light systems have since come and gone, and although they may be comparable to what is described below, each system is unique and should be studied on its own merits for the treatment of inflammatory acne vulgaris.

The first FDA-approved blue light was a high-intensity, narrow-band source with an absorption peak at 417 nm. Commercially, this machine was known as the ClearLight™ Acne PhotoClearing System (CureLight, Yokneam, Israel). Its FDA clearance was for the treatment of mild-to-moderate inflammatory acne vulgaris and its use in the medical field, as well as its safety and efficacy, is well documented in the medical literature. The recommended use for this device was to treat patients twice per week for up to 4 weeks for appropriate inflammatory acne vulgaris lesion control.

Kawada et al⁸ reported that by using a blue light source for inflammatory acne vulgaris twice weekly for 5 weeks, inflammatory acne lesions were reduced, on average, by 64% in the 30 patients they treated. Shalita et al ⁹, in a multicentre clinical trial for the ClearLight system, reported an 80% significant improvement in treating 35 individuals with mild-to-moderate inflammatory acne vulgaris twice weekly for 4 weeks. Of note in this clinical trial was, following therapy, further acne vulgaris improvement in many of the patients entered into the study. Adverse events were not seen and all skin types were successfully treated in the trial.

[pull_quote align=”right” ]Blue light therapy for inflammatory acne vulgaris is a true and tried method for improving the outcomes of those suffering from acne vulgaris.[/pull_quote]

Gold et al then reported on 40 individuals treated with the ClearLight system for mild-to-moderate inflammatory acne vulgaris¹⁰. The patients in this clinical trial also received twice weekly blue light therapy for 4 weeks and were then followed 1 and 3 months following their final ClearLight treatment. A 43% reduction in inflammatory acne vulgaris lesions was noted. Adverse events, similar to the previous work, were not observed in this study and results were noted to further improve in many during the follow-up period. When comparing the Gold and Shalita clinical trials, Gold’s data included both ‘responders’ and ‘non-responders’, something that was not done in the Shalita clinical trial. It has been noted that, upwards of 20% of individuals treated with the blue light system are non-responders. Adding them into the total percentage of clearance would certainly have brought the two clinical trials closer together in numbers and percentage clearance.

The ClearLight high-intensity blue light system is not currently commercially available, and its replacement device, known as the iClear, is also no longer available. Many still use these light sources in their everyday clinical practice and have made significant differences for many suffering from inflammatory acne vulgaris, which has either not been adequately controlled with medical therapy or the patient is looking for a faster path to acne lesion clearance.