Handheld LED array device in the treatment of acne vulgaris

Journal of Drugs in Dermatology, April, 2008 by Neil S. Sadick

Introduction

Acne is a chronic, inflammatory disease of the pilosebaceous units of the face, chest, and back. In the US, census data and prevalence reports indicate approximately 40 million adolescents and 25 million adults (85% of the population) have some form of acne, with 30% requiring physician intervention. (1-3)

The mainstays of current acne treatments are retinoids and antibiotics, however treatment failure rates vary. Retinoid therapy carries a poor side-effect profile and displays teratogenicity (4) and can only be prescribed by member physicians of the System to Manage Accutane-Related Teratogenicity (SMART) program and the development of bacterial resistance in antibiotic therapy is widely documented. (5) Topical preparations may also cause significant side effects including skin irritation and these effects may lead to noncompliance with treatment. (6) Such noncompliance is one of the most common aspects of regimen failure in acne therapy, (7) which highlights the need for an alternative therapy or a combination of therapies for patients who fail to respond adequately to current treatments, develop problematic side effects, or are noncompliant.

Photodynamic therapy is the use of light to activate exogenously administered or endogenously formed photosensitizers within the cell, forming singlet oxygen and other transient free radicals, inducing cellular death by apoptosis. The success of blue light for treating mild to moderate acne has been proven to varying degrees of success using photodynamic therapy. (8-12) Propionibacterium acnes is known to produce endogenous photosensitizers called porphyrins, the major components of which are coproporphyrin III (13,14) and protoporphyrin IX (PPIX). (15) Coproporphyrin III and protoporphyrin IX mainly absorb visible light at 400 nm to 415 nm. (13,14)

Blue light in combination with red has been proven to be an effective therapy in the treatment of acne vulgaris. (15-17) Papageorgiou et al, and subsequently Golberg and Russell and Lee et al, proposed that blue light and red light acted synergistically in improving acne by combining the antibacterial and anti-inflammatory action of blue and red light, respectively. (15-17)

The objective of this study was to evaluate the efficacy of blue light (415 nm) in combination with red (633 nm) in the reduction of inflammatory lesions on the face of subjects with mild to moderate acne vulgaris after a course of 8 light treatments delivered by a handheld unit, and self-administered by the patient over a period of 4 weeks.

Materials and Methods

Subjects

Twenty-one subjects (38% male, 62% female; age range: 14-21 years) with Burton grades 3 and 4 were recruited. Subjects had not used topical, oral, or systemic treatments for 4 weeks and had not received oral retinoids for 6 months prior to the study. Subjects were recruited during December 2006. Treatments were administered between January and February 2007. All subjects gave informed consent to the treatment and had been prescreened before inclusion on the study. Subjects were allocated to a single treatment group. No control group was used in this study. An independent ethics review panel approved the study.

Light Source

The handheld unit (Omnilux clear-U[TM], Photo Therapeutics Inc, Carlsbad, CA) consisted of an air cooled, fixed planar array of light-emitting diodes emitting at 415 nm (40 mW/[cm.sup.2]) and 633 nm (70 mW/[cm.sup.2]). The active light-emitting diode area measured 60 mm by 50 mm and was used to illuminate the subject treatment area.

Treatment

Before the treatment course, subjects were instructed to read the user manual on the use of the handheld light source and were monitored during the study to assess the subjects' understanding of how to operate the equipment. Each subject was given 1 of 6 locations on the face to treat: left or right forehead, left or right cheek, nose or chin. Chest and back were excluded. Locations were randomly allocated using a modification of the Global Acne Grading System (GAGS). Subjects were issued with a nonmedicated soap for the duration of the trial.

Each week, the subject administered 2 alternate exposures: blue light (415 nm; 40 mW/[cm.sup.2], 48 J/[cm.sup.2]) for a 20-minute duration and red light (633 nm; 70 mW/[cm.sup.2], 126 J/[cm.sup.2]) for a 30-minute duration. The unit was operated by each subject and held in contact with the subject's face for the duration of the treatment. A 2 to 3 day interval was instructed between blue and red light treatments. The weekly treatments were continued for the full study period of 4 weeks (total of 8 treatments).

Clinical Assessments

Burton acne grading and Fitzpatrick skin type were recorded for all subjects at baseline. Acne assessments were conducted using lesion counts to include the treated area as identified by the GAGS system. Lesions included in the count were comedones, papules, pustules, and nodules. Each lesion present was assigned a value of 1 in the lesion count. Acne was assessed at baseline and weeks 2, 4, 8, and 12. The principle-investigating physician (nonblinded) conducted assessments.