Melasma, which tends to grow on both sides of the cheeks in women in their 40s, can appear under the effect of many reasons such as ultraviolet radiation, pregnancy and heredity. Chloasma is a symmetrical yellowish-brown pigmentation spot that occurs on the face, mostly seen in young and middle-aged women. Long-term ultraviolet irradiation can damage the epidermal barrier of the skin and increase the release of inflammatory factors, which promotes melanin synthesis and transportation; during pregnancy, the effect of estrogen and progesterone can increase pigment production and form spots; in addition, genetic factors are also prone to the formation of chloasma on the skin. The lesions are symmetrically distributed on the cheeks, cheeks or forehead, nose, etc. They are brown or yellow-brown patches with clear edges and different sizes, which may last for months or years. In addition to chloasma, there may be sun spots, seborrheic keratosis, etc. Specific treatments suggest that patients should go to regular medical institutions to clarify the cause of the disease and then do corresponding treatments, such as applying topical medications, systemic medications, or lasers, etc., and usually try to minimize the exposure to sunlight.