Skin pigmentation is a result of melanin produced by melanocytes in the epidermis. Melanocyte activity, along with the type and distribution of melanins, is the main driver for diversity of skin pigmentation. Dark melanin acts to protect against the deleterious effects of ultraviolet (UV) radiation, including photo-aging and skin cancer formation. In turn, UV radiation activates skin melanocytes to induce further pigmentation (i.e., “tanning pathway”). The well-characterized MSH/MC1R-cAMP-MITF pathway regulates UV-induced melanization. Pharmacologic activation of this pathway (“sunless tanning”) represents a potential strategy for skin cancer prevention, particularly in those with light skin or the “red hair” phenotype who tan poorly after UV exposure due to MC1R inactivating polymorphisms. Skin hyperpigmentation can also occur as a result of inflammatory processes and dermatological disorders such as melasma. While primarily of cosmetic concern, these conditions can dramatically impact quality of life of affected patients. Several topical agents are utilized to treat skin pigmentation disorders. Here, we review melanogenesis induced by UV exposure and the agents that target this pathway.

皮肤色素沉着是表皮中黑色素细胞产生黑色素的结果。黑色素细胞活动以及黑色素的类型和分布是皮肤色素沉着多样性的主要驱动因素。深色黑色素可防止紫外线 (UV) 辐射的有害影响，包括光老化和皮肤癌的形成。反过来，紫外线辐射会激活皮肤黑色素细胞以诱导进一步的色素沉着（即，“晒黑途径”）。充分表征的 MSH/MC1R-cAMP-MITF 通路调节紫外线诱导的黑化。该途径的药理学激活（“免晒美黑”）代表了预防皮肤癌的潜在策略，特别是在那些皮肤较浅或“红头发”表型的人中，这些人在紫外线照射后由于 MC1R 失活多态性而晒黑。炎症过程和皮肤病如黄褐斑也可能导致皮肤色素沉着过度。虽然主要是美容问题，但这些情况会显着影响受影响患者的生活质量。几种局部药剂用于治疗皮肤色素沉着障碍。在这里，我们回顾了由紫外线照射引起的黑色素生成和针对该途径的试剂。