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Two recent studies evaluating the efficacy in the treatment of acne with a combination of blue light and red light show increased efficacy over blue light alone for patients with mild to severe acne and for those with Fitzpatrick skin phototype IV.
In the treatment of acne, blue light has been shown to offer efficacy as a sound treatment regimen, but in two recent studies evaluating the outcome when red light is added to the mix, researchers found increased efficacy over blue light alone for patients with mild-to-severe acne and for those with Fitzpatrick skin phototype IV.
In the first study, researchers from the Mount Sinai School of Medicine, New York, treated 24 subjects with mild-to-severe symmetric facial acne vulgaris with eight sessions of treatments. The treatments, conducted twice per week, three days apart, alternated between 415 nm blue light (20 minutes/session, 48 J/cm2) and 633 nm red light (20 minutes/session, 96 J/cm2) from a light-emitting diode (LED)-based therapy system. (J Cosm Laser Ther. 2006; 8:71–75).
Patients included those with Fitzpatrick skin types II through V, and they received a mild microdermabrasion before each session. In assessments of acne at the four-week follow-up, the mean lesion count reduction was significant at 46 percent (p=0.001). At the 12-week follow-up, the mean lesion count reduction was also significant at 81 percent (p=0.001).
Severe acne showed a marginally better response than mild acne, and the researchers reported that side effects were minimal and transitory. Comedones did not respond as well as inflammatory lesions.
A variety of lasers and light-based therapies have shown some efficacy in treating acne; however, the combination of blue and red LED has distinctive benefits over other modalities, according to David J. Goldberg, M.D., clinical professor of dermatology and director of laser research at the Mount Sinai School of Medicine.
"LED treatments are painless, a fact not true about any other laser- or light-based treatment," says Dr. Goldberg, who was lead researcher on the study.
"In addition, LED treatments can be used in all skin colors, a fact not true about many other laser- or light-based treatments, and because LED treatments promote no thermal effect, they cannot scar - a fact not true about any other laser- or light-based treatment," Dr. Goldberg tells Dermatology Times.
In a separate study, researchers at the National Medical Center in Seoul, Korea, treated 24 patients with mild- to-severe acne and Fitzpatrick skin type IV to alternating blue (415 nm) and red (633 nm) light treatments twice a week for four weeks. (Lasers Surg Med. 2007 Feb;39(2):180-188).
After assessments conduced at two, four and eight weeks after the final treatment, the final mean percentage of improvements in noninflammatory and inflammatory lesions was 34.28 percent and 77.93 percent, respectively. In addition, 14 patients reported the added benefit of having spontaneous brightening of skin tone and improved skin texture.
"The newly found brightening effect of this therapy would be appealing to Asians, although the exact efficacy and mechanism of this effect need further investigations," the researchers say.
Blue light therapy at levels of 415 nm has been shown to activate coproporphyrin III and protoporphyrin IX, subsequently destroying P. acnes bacteria and resulting in clinical improvement in patients with acne, the researchers report.
Red light therapy at levels of 633 nm is, meanwhile, less effective at activating coproporphyrin III than blue light. However, it is a potent activator of protoporphyrin IX, also found in P. acnes bacteria, and the researchers suggest that since it penetrates deeper into tissue than blue light, the red light could actively destroy P. acnes bacteria found in the lower regions of the sebaceous gland.
Red light has also been shown to demonstrate anti-inflammatory properties by influencing cytokine release from macrophages.