Department of Dermatology, Maulana Azad Medical College and Associated Lok Nayak Hospital, Delhi, India.
Indian J Dermatol Venereol Leprol. 2020 Jan-Feb;86(1):8-17. doi: 10.4103/ijdvl.IJDVL_633_18.
Melasma is a common, acquired, symmetrical hypermelanosis. It negatively impacts the patient's quality of life and responds poorly to treatment. Although earlier classified as epidermal and dermal, melasma is now thought to be a complex interaction between epidermal melanocytes, keratinocytes, dermal fibroblasts, mast cells, and vascular endothelial cells. Factors influencing melasma may include inflammation, reactive oxygen species, ultraviolet radiation, genetic factors, and hormones. With a better understanding of the pathogenesis of melasma and the realization that targeting melanin synthesis alone is not very effective, treatments focussing on newly implicated factors have been developed. These include agents targeting hyperactive melanocytes, melanosomal transfer to keratinocytes, defective skin barrier, the mast cells, vasculature, and estrogen receptors as well as drugs with anti-inflammatory and antioxidant activity. Many of these newer agents are botanicals with multimodal mechanisms of action that offer a better safety profile when compared with the conventional drugs. There has also been a focus on oral agents such as tranexamic acid, flutamide, and ascorbic acid. It has been suggested that the "triple therapy of the future" may be a combination of hydroquinone, an antiestrogen and a vascular endothelial growth factor inhibitor, as the "ideal" skin-lightening agent.
黄褐斑是一种常见的获得性对称性色素沉着过度。它会降低患者的生活质量，并且对治疗反应不佳。尽管早期被归类为表皮和真皮，但现在认为黄褐斑是表皮黑素细胞、角质形成细胞、真皮成纤维细胞、肥大细胞和血管内皮细胞之间的复杂相互作用。影响黄褐斑的因素可能包括炎症、活性氧、紫外线辐射、遗传因素和激素。随着对黄褐斑发病机制的认识不断深入，并且认识到仅针对黑色素合成的治疗效果并不理想，因此开发了针对新发现的因素的治疗方法。这些方法包括针对异常活跃的黑素细胞、黑素小体向角质形成细胞转移、皮肤屏障缺陷、肥大细胞、血管和雌激素受体的药物，以及具有抗炎和抗氧化活性的药物。这些较新的药物中有许多是植物药，其具有多模式作用机制，与传统药物相比，具有更好的安全性。人们还关注氨甲环酸、氟他胺和抗坏血酸等口服药物。有人提出，“未来的三联疗法”可能是氢醌、抗雌激素和血管内皮生长因子抑制剂的联合应用，因为它们是“理想”的皮肤美白剂。
