Dark spots on the face are usually a kind of facial melanin deposition skin disease formed by the increase of skin melanin, which is more common in life and may be related to endocrine disorders, sun exposure, external stimuli and diseases, etc. 1. Endocrine disorders: daily stress, lack of sleep, staying up late and other factors can lead to endocrine disorders and poor skin metabolism, resulting in increased melanin. In addition, as we grow older, the metabolism of the skin tends to slow down, which also easily causes skin pigmentation and dark spots on the face; 2, sun exposure: sun protection measures may not be in place, caused by long-term exposure to ultraviolet rays of the sun. Because the ultraviolet ray can obviously stimulate the melanocytes in the skin, promote the synthesis of melanin, thus leading to the appearance of dark spots on the face; 3, external stimulation: expired or poor quality cosmetics may contain metal substances, such as lead, mercury, arsenic, etc., improper use can cause poisoning or allergy, can also appear dark spots on the face; 4, disease: such as various inflammatory diseases, inflammation caused by epidermal basal layer cell liquefaction degeneration, leading to melanin fall into the dermis. This causes melanin to fall to the superficial layer of dermis, and after the inflammation subsides, pigmentation remains, which is manifested as black spots on the face. In addition, if you suffer from chronic diseases, such as liver disease, anemia, etc., you can also have black spots on your face.