Classification of spots: 1.Freckles: related to heredity, 3% related to autosomes and blood, the color is aggravated after sun exposure, distributed as dots isolated from each other, the diameter does not exceed 0.5 cm, often distributed on cheeks, hands and shoulders, starting to appear at the age of 5-7, cannot be eradicated but can only fade. 2.Chloasma: also known as butterfly spot and liver spot, it is light brown and flaky, with variable size, clear border, irregular shape and not higher than the skin, commonly found on the face and symmetrically on both cheeks, mainly due to endocrine and female hormonal imbalance. 3.Sun spots: acquired factors, caused by ultraviolet rays, irregular in size. 4.Age spots: caused by natural aging, physiological decline and metabolic retardation, the shape is mostly higher than the skin, usually on the face and hands. The causes of spots: 1. Internal factors 1. Stress When people are under stress, they will secrete adrenaline to prepare for the stress. If a person is under stress for a long time, the balance of human metabolism will be disrupted, the supply of nutrients needed by the skin will tend to slow down, and the pigment mother cells will become very active. 2, hormonal imbalance The female hormone estrogen contained in the contraceptive pill will stimulate the secretion of mylanin cells and form uneven spots. The spots formed by the contraceptive pill will stop after the interruption of taking the pill, but they will still stay on the skin for a long time. In pregnancy, due to the increase of female hormone estrogen, spots will easily appear from the 4th to 5th month of pregnancy, and most of the spots that appear at this time will disappear after delivery. However, sometimes the newly grown spots will not disappear after delivery, so more attention is needed. 3.Slow metabolism The spots will also appear when the metabolism of liver is not normal or the ovarian function is reduced. The problem of pigmentation is aggravated by poor metabolism or endocrine imbalance when the body is in a sensitive state. When the body is not in normal condition, ultraviolet radiation will also accelerate the formation of spots. 4.Hereditary gene If there are parents with long spots, the probability of having long spots is very high, which can be judged as the role of hereditary gene to a certain extent. Therefore, especially for those who have long spots in the family, we should pay attention to avoid UV radiation, which is one of the important factors that trigger long spots, and this is what we must pay attention to in order to prevent spots. External Factors 1. Ultraviolet light When irradiating ultraviolet light, the human body will produce a lot of mellanin pigment in the basal layer in order to protect the skin. So in order to protect the skin will gather more pigments in sensitive parts. Frequent exposure to strong sunlight not only promotes skin aging, but also causes skin disorders such as dark spots, freckles and other pigmentation. 2, bad cleaning habits Because of strong cleaning habits to make the skin become sensitive, which will stimulate the skin. When the skin is sensitive, the body will secrete a lot of melanin pigment in order to protect the skin, and when there is excess pigment, there will be spots, blemishes and other skin pigmentation problems. 3, wrong use of cosmetics The use of cosmetics that are not suitable for their skin, resulting in skin allergies, in the process of treatment such as excessive exposure to ultraviolet light, the skin will be in order to resist external aggression, in the inflammatory parts of the collection of mellanin pigment, so that the problem of hyperpigmentation will occur.