Common causes of chloasma in men include ultraviolet radiation, sex hormone level disorder, race and heredity. 1. Ultraviolet irradiation: Generally, after long-term ultraviolet irradiation, the epidermal barrier will be damaged, which leads to the enhancement of tyrosinase activity and the promotion of melanin synthesis and transit, forming chloasma. This is the main reason for chloasma in men. 2. Sex hormone level disorder: Long-term staying up late, laboring, eating spicy and stimulating food, etc. may induce chloasma by sex hormone level disorder in the body. It is also related to certain chronic diseases, such as chronic hepatitis or tuberculosis, etc. Men with hereditary chloasma need to be alert to other systemic diseases. 3. Race and heredity: Melasma has hereditary tendency, if there are many people with melasma in the family, the prevalence rate of the next generation will increase. Men with chloasma are recommended to go to regular hospitals for treatment, and under the guidance of professional doctors, they should have reasonable treatment to improve the symptoms. Normally, it is necessary to pay attention to sun protection and avoid direct exposure to ultraviolet rays.