Treatment of Benign Pigmented Lesions Using a Long-Pulse Alexandrite Laser

November 2012 | Volume 11 | Issue 11 | Original Article | 1327 | Copyright © November 2012


Douglas Winstanley DO, Travis Blalock MD, Nancy Houghton BS, and E. Victor Ross MD

Scripps Clinic Laser and Cosmetic Dermatology, San Diego, CA

Abstract
Background: To evaluate the efficacy of a novel long-pulse alexandrite laser with contact cooling in the treatment of benign pigmented lesions.
Methods: Five patients were enrolled in the study. All patients presented with epidermal pigmented lesions on the arms, hands, chest, or legs. Patients were all female with a mean age of 59 years. At the initial evaluation, baseline pigment readings were determined with a pigment meter. Test spots were performed with escalating doses of alexandrite laser (ClearScan ALX, Sciton, Palo Alto, CA) deployed by a 7-mm spot equipped with a 30 mm x 30 mm scanner and a 10-ms pulse duration. Contact cooling was used, and temperature was maintained at 18°C to 20°C. Patients returned 4 to 7 days after test spots for evaluation for the purpose of optimizing settings. The highest settings that allowed for epidermal preservation and crusting of the hyperpigmented lesions were applied for the remainder of the treatment zones. Determinations of improvement were made by evaluation of photographs with standard settings using polarized and nonpolarized images. At each appointment, baseline pigment measurements were made to ensure there were no significant changes between treatment sessions. Two treatment sessions were performed approximately 4 weeks apart, and the final evaluation was 3 months after the final treatment.
Results: Evaluation by a panel of blind observers determined a mean improvement of approximately 30%. Darker lesions responded better than lighter lesions. So-called low-contrast lesions performed the poorest. Pain was approximately 2/10 with the use of 5% lidocaine numbing cream applied approximately 45 minutes before each procedure. Pain was most severe where there was underlying hair.
Conclusion: A long-pulse alexandrite laser equipped with contact cooling can achieve significant pigmentation improvement.

J Drugs Dermatol. 2012;11(11):1327-1330.

INTRODUCTION

Treatment of solar lentigines can be accomplished through several modalities, including the use of cryogen, hyfrecation, and light-based options. Based on the theory of selective photothermolysis,1 quality-switched (QS) lasers have been employed to treat pigmented lesions with great success. The high energy output and short pulse durations offer precise, spatially confined heating of epidermal pigmented lesions while avoiding significant heat diffusion from the target.2 However, for patients who have dyschromia involving a large portion of the face or with chronic bronzing, treatment of large areas becomes labor-intensive and timeconsuming. Intense pulsed light devices have the benefit of larger spot sizes with efficacy that approaches that of QS lasers in the treatment of pigmented lesions.3,4 Therefore, they have utility in treating larger areas. As an additional alternative, the efficacy and safety of treatment of these lesions with a longpulse alexandrite laser with fixed pulse duration has been reported. 2,5 The following study further demonstrates the safety and efficacy of a new long-pulse alexandrite laser (ClearScan ALX, 755 nm, Sciton, Palo Alto, CA) that employs contact cooling in the treatment of superficial pigmented lesions.

METHODS

Patients

A total of 5 patients were enrolled and treated in this prospective study after approval from the Scripps Institutional Review Board. Each patient was advised of the risks and benefits regarding the procedure, and consent was obtained before treatment. The study conformed to the guidelines of the 1975 Declaration of Helsinki. Patients in this study had a mean age of 59 years and were all female. All patients had Fitzpatrick skin types II and III, with 4 patients having type II skin. All had clinically diagnosed lentigines on the arms, hands, chest, or legs.
Exclusion criteria included Fitzpatrick skin types V and VI, immunocompromised patients, history of connective tissue disease, age younger than 18 years or older than 75 years, the inability to read and comprehend English, known photosensitivity, pregnancy, recent tan, history of poor wound healing, scarring in the treatment area and history of keloid formation, active local or systemic infection, or history of isotretinoin use within 6 months before the initiation of treatment.

Procedure

Each patient enrolled in the study underwent an initial evaluation and test spot treatment to determine the most efficacious and safe fluence for each individual. Follow-up full treatments of designated areas were performed at subsequent visits.
Sites were photographed using a digital camera (D70, Nikon, Melville, NY), with and without a cross-polarizing filter (Canfield Imaging Systems, Fairfield, NJ). Topical anesthetic of 5% lido-