The evolution of melasma therapy: targeting melanosomes using low-fluence Q-switched neodymium-doped yttrium aluminium garnet lasers

Melasma is an acquired disorder of pigmentation that commonly affects women with phototypes III-V, and it has a negative impact on the quality of life in affected individuals. It presents clinically as symmetric tan or brown patches on the face, most often involving the forehead, cheeks, perioral region, and periorbital region. On histologic examination, there is increased melanin in the epidermis and/or an increased number of melanosomes in the dermis, with a normal number of highly melanized and dendritic melanocytes. The mainstay of treatment is the use of sunscreen along with topical medications that suppress melanogenesis. Clearance is usually incomplete and recurrences or exacerbations are frequent, probably because of the poor efficacy in clearing dermal melanosomes. Treatment with high-energy pigment-specific lasers, ablative resurfacing lasers, and fractional lasers results in an unacceptably high rate of postinflammatory hyper- and hypopigmentation and rebound melasma. Recently, promising results have been achieved with low-fluence Q-switched neodymium-doped yttrium aluminium garnet laser treatment, which can selectively target dermal melanosomes without producing inflammation or epidermal damage, in all skin phototypes. This article reviews the current treatment modalities for melasma, the rationale for using and the clinical results of combination therapy with low-fluence Q-switched neodymium-doped yttrium aluminium garnet lasers.