INTRODUCTION
Melasma is a common cause of acquired facial hyperpigmentation. Although the etiology is not entirely established, multiple factors such as genetic susceptibility, ultraviolet (UV) exposure, pregnancy, sex hormones, contraceptive pills, cosmetics, and medications have been identified as contributing factors. Adequate UV protection and topical lightening agents are considered as first-line treatments for melasma, with the best therapeutic results achieved in epidermal melasma. Chemical peels and laser/light-based therapies are most often reserved as second- and third-line approaches.1-4
Hydroquinone used as monotherapy or in triple combination creams is the most popular and effective topical treatment for melasma. However, adverse effects from hydroquinone such as contact dermatitis, irritation, leukoderma, and ochronosis highlight the need for safer alternatives for melasma treatment.1-3
Topical silymarin has been reported to be safe and effective in melasma.5-8 Silymarin is a natural polyphenolic flavonoid derived from milk thistle seeds (Silybum marianum). It is a mixture of 3 structural components: silibinin, silydianin, and silychristin. Silibinin is the main component and the most biologically active, with potent antioxidant properties.9 Previous literature has demonstrated cutaneous protection effects of silymarin such as anti-inflammation and the reduction of UV-induced oxidative stress, apoptosis, and DNA damage.9-11 Moreover, silymarin demonstrates inhibition of melanogenesis without toxic effects and inhibits L-DOPA oxidation activity of tyrosinase.12 These properties of silymarin could be beneficial as a topical treatment in melasma. The aim of this study is to compare the efficacy and safety of 1.4% silymarin with 2% hydroquinone for the treatment of epidermal and mixed-type melasma.
Hydroquinone used as monotherapy or in triple combination creams is the most popular and effective topical treatment for melasma. However, adverse effects from hydroquinone such as contact dermatitis, irritation, leukoderma, and ochronosis highlight the need for safer alternatives for melasma treatment.1-3
Topical silymarin has been reported to be safe and effective in melasma.5-8 Silymarin is a natural polyphenolic flavonoid derived from milk thistle seeds (Silybum marianum). It is a mixture of 3 structural components: silibinin, silydianin, and silychristin. Silibinin is the main component and the most biologically active, with potent antioxidant properties.9 Previous literature has demonstrated cutaneous protection effects of silymarin such as anti-inflammation and the reduction of UV-induced oxidative stress, apoptosis, and DNA damage.9-11 Moreover, silymarin demonstrates inhibition of melanogenesis without toxic effects and inhibits L-DOPA oxidation activity of tyrosinase.12 These properties of silymarin could be beneficial as a topical treatment in melasma. The aim of this study is to compare the efficacy and safety of 1.4% silymarin with 2% hydroquinone for the treatment of epidermal and mixed-type melasma.
STUDY DESIGN
This split-face, double-blind randomized study was approved by the Ramathibodi Institutional Ethical Committee Review Board on May 22, 2017, Certificate No. MURA 2017/267; and conformed to the ethical guidelines of the 1975 Declaration of Helsinki and all its revisions. Written informed consent was obtained from patients before enrollment.
