Laser and Other Light Therapies for the Treatment of Acne Vulgaris: Systematic Review

F.L. Hamilton; J. Car; C. Lyons; M. Car; A. Layton; A. Majeed

Disclosures

The British Journal of Dermatology. 2009;160(6):1273-1285. 

In This Article

Abstract and Introduction

Abstract

Background: Acne is common and can lead to scarring of the skin, as well as to psychological distress and reduced self-esteem. Most topical or oral treatments for acne are inconvenient and have side-effects. Laser and other light therapies have been reported to be convenient, safe and effective in treating acne.
Objectives: To carry out a systematic review of randomized controlled trials of light and laser therapies for acne vulgaris.
Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, PsycInfo, LILACS, ISI Science Citation Index and Dissertation Abstracts International for relevant published trials.
Results: We identified 25 trials (694 patients), 13 of light therapy and 12 of light therapy plus light-activated topical cream (photodynamic therapy, PDT). Overall, the results from trials of light alone were disappointing, but the trials of blue light, blue-red light and infrared radiation were more successful, particularly those using multiple treatments. Red-blue light was more effective than topical 5% benzoyl peroxide cream in the short term. Most trials of PDT showed some benefit, which was greater with multiple treatments, and better for noninflammatory acne lesions. However, the improvements in inflammatory acne lesions were not better than with topical 1% adapalene gel, and the side-effects of therapy were unacceptable to many participants.
Conclusions: Some forms of light therapy were of short-term benefit. Patients may find it easier to comply with these treatments, despite the initial discomfort, because of their short duration. However, very few trials compared light therapy with conventional acne treatments, were conducted in patients with severe acne or examined long-term benefits of treatment.

Introduction

Acne has a prevalence of 70-90% among teenagers[1,2] and some people continue to have acne in adult life. It can lead to low self-esteem, loss of confidence and depression.[3] It can even affect productivity and employability,[4] and quality of life scales have assessed the impact of acne as similar to epilepsy or asthma.[3] Scarring of the skin is also common and is difficult to treat.[5]

Conventional treatments for acne tend to be inconvenient and associated with side-effects and this has prompted a search for more acceptable therapies. Acne often improves after exposure to sunlight, and this observation has led to the development of laser and other light therapies.[6,7] These are thought to work either by killing Propionibacterium acnes directly or by selectively damaging sebaceous glands, depending on the wavelength of light used.

Propionibacterium acnes produces porphyrins which absorb light to form singlet oxygen radicals, which are highly reactive and kill the bacteria.[8] Peak absorption occurs at 415 nm, in the middle of the blue light wavelengths.[8,9] Green light is also absorbed by porphyrins and penetrates deeper into the skin.[7] Red light is less effective at activating porphyrins but penetrates even more deeply into the skin, where it may have a direct effect on inflammatory mediators.[10] Infrared lasers, radiofrequency devices and low-energy pulsed dye lasers are thought to improve acne by thermally damaging sebaceous glands directly.[11,12]

Photodynamic therapy (PDT) uses light-activated creams which are absorbed into the pilosebaceous unit to amplify the response to light therapy. These agents include methyl aminolaevulinate (MAL),[13,14] 5-aminolaevulinic acid (ALA)[15,16] and indocyanine green.[17] PDT tends to be more painful than light alone, and more likely to produce erythema, oedema, initial worsening of acne, crusting and epithelial exfoliation. The severity of side-effects depends partly on skin type,[18] as melanocytes absorb light due to their pigment.

Optical therapies are generally not available through the National Health Service in the U.K., or from health insurance companies, so patients access them through private providers. Estimating the U.K. market for these procedures is difficult because there is no current requirement for external audit. The largest subsector of this category is optical therapy, but available figures combine all acne, hair removal and skin rejuvenation treatments. A recent Mintel report[19] suggests that approximately 166 000 treatments were carried out in 2005, representing a market value of about £42 million, but this is likely to be an underestimate. Similarly, in the U.S.A. there are no accurate centrally available figures for light therapy, but the American Society for Aesthetic Plastic Surgery[20] estimates that 576 509 'laser skin resurfacing' procedures were carried out in 2006 at a cost of around $610 million.

Clearly, patients are prepared to spend large sums of money on optical therapies for the treatment of acne. However, to date, the trials of light therapy have been small and the results conflicting. Given that people with moderate to severe inflammatory acne are vulnerable to commercial exploitation, it is important to review systematically the available evidence to determine to what extent laser and other light treatments improve acne.

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