The Clinical and Histological Effect of a Low-Fluence Q-Switched 1,064-nm Neodymium: Yttrium-Aluminum-Garnet Laser for the Treatment of Melasma and Solar Lentigenes in Asians: Prospective, Randomized, and Split-Face Comparative Study

BACKGROUNDThe low-fluence Q-switched 1,064-nm neodymium:yttrium-aluminum-garnet laser (QSNYL) is popular for melasma treatment among Asians. OBJECTIVEThis study was to evaluate the clinical and histological effects of the low-fluence QSNYL for treatment of melasma and solar lentigenes. MATERIALS AND METHODSIn this randomized split-face clinical study, 22 patients with melasma or solar lentigo received low-fluence QSNYL weekly for 10 sessions on one cheek. The treatment efficacy was determined by Mexameter skin colorimetry, physician and patient assessment, and by evaluating histological changes. RESULTSThe treated sides had statistically significant reductions in the melanin and erythema indices (EI); 50.0% of melasma and 62.5% of solar lentigo patients had >50% clearance after the final treatment. The increased EI, vascularity, and mast cell activity in patients with melasma and large-sized solar lentigo showed no improvement. The recurrence rates were 16.7% and 12.7% for melasma and solar lentigo, respectively. Postinflammatory hyperpigmentation developed in 1 patient, but no serious side effects were noted. CONCLUSIONLow-fluence QSNYL is effective in treating melasma and small type solar lentigo in Asians. The authorsʼ study also demonstrated that lesion thickness, vascularity, and mast cell activity can be used to predict the efficacy of the treatment of these lesions.