New Melasma Treatment by Collimated Low Fluence Q-switched Nd : YAG Laser / 대한피부과학회지

ABSTRACT

BACKGROUND: Laser treatment in melasma has previously failed because of the resulting inflammation and consequent pigmentation and excessive thermal damage caused by the use of high fluence. OBJECTIVE: This study is aimed at establishing the concept of the collimated low fluence Q-switched Nd YAG laser as a treatment for melasma by investigating its therapeutic effects clinically as well as histopathologically. METHODS: 27 patients were treated weekly with Q-switched Nd YAG laser (1,064 nm wavelength, 7 mm spot size, 1.6~2.5 J/cm2 fluence) for 8 weeks. The results were evaluated based on standardized clinical images that used Robo skin analyzer, spectrophotometer, MASI score and general severity. RESULTS: 17 (58.8%) patients showed "GOOD" (50~75% improvement) and no case of full recurrence was examined and partial recurrence was detected in 12/17 patients. Common adverse effects include pain, erythema, and temporary edema. Rarely partial hypopigmented macules and diffuse hyperpigmentation appeared. Additional studies, such as immunohistochemical examination and electron microscopic examination, are also currently in progress. CONCLUSION: The collimated low fluence Q-switched Nd YAG Laser is effective in melasma treatment. This treatment method is a new concept that can be described as selective photothermolysis with minimal thermal damage and inflammation reaction to affected tissues by pigmentation. We consider this treatment method should be regarded as Minimized Selective Photothermolysis (MSP) that will provide a new effective treatment for melasma.