Impact of Air Pollution on Skin Pigmentation: Mechanisms and Protective Strategies.

Air pollution, a critical global health challenge, impacts nearly the entire world population, with low- and middle-income countries bearing a disproportionate burden. In 2021, the World Health Organization (WHO) stated that air pollution is the most urgent and largest public health problem. While its role in respiratory and cardiovascular diseases is well established, its effects on skin, particularly in inducing pigmentation, remain underexplored. The pollutants, particularly particulate matter, penetrate the skin and activate pathways like the aryl hydrocarbon receptor (AhR) and promote the production of reactive oxygen species (ROS). This oxidative stress exacerbates inflammatory responses and triggers melanocyte stimulation, leading to hyperpigmentation disorders such as melasma, senile lentigines, and diffuse facial pigmentation. Additionally, the synergistic interaction of air pollution with ultraviolet radiation (UVR) exacerbates its impact on skin. Emerging evidence highlights the potential of antioxidants such as N-acetylcysteine, vitamin E, and niacinamide as protective measures against the effects of air pollution. It is vital that air pollution is recognized as a significant contributor to inflammatory skin disorders and skin pigmentation, patients are made aware of the need for preventive measures, and policymakers are cognizant of the urgent need for sustainable environmental policies to reduce its impact. This narrative review focuses on current knowledge on pollution-induced skin pigmentation, preventive measures, and skin care strategies to mitigate pollution-induced pigmentary changes.