Question - The article cited below notes melasma is “a common, acquired skin condition that is characterized by symmetric, irregular brown or grayish brown patches on sun-exposed areas such as the forehead and malar prominences and less commonly the neck and forearms.” The most common treatment for melasma involves topical applications of the chemical hydroquinone to induce hypopigmentation. What is the mechanism for this effect?
Answer- According to the cited article, “Hydroquinone exerts pleiotropic hypopigmenting effects via weak inhibition of tyrosinase, potent cytotoxicity toward melanocytes, degradation of melanosomes, depletion of glutathione, and inhibition of DNA and RNA synthesis.” (Jow T and Hantash BM. Hydroquinone-induced depigmentation: case report and review of the literature. 2014 Dermatitis 25(1): e1-e5)