1.Classification of spots 1.Freckles: related to heredity, 3% related to autosomes and blood, the color is aggravated after sun exposure, the distribution is dotted and isolated from each other, the diameter does not exceed 0.5 cm, often distributed on the cheeks, hands and shoulders, starting to appear at the age of 5-7 years old, cannot be eradicated but can only fade; 2.Chloasma: also known as butterfly spot, liver spot, showing light brown, flaky, the size of the spot varies, the border is clear. Irregular shape, not higher than the skin, common in the face, symmetrical in the cheeks, mainly due to endocrine, female hormonal imbalance; 3, sun spots: acquired factors, caused by ultraviolet rays, the formation of irregular size; 4, age spots: natural aging, physiological decline, metabolic retardation caused by the shape of most higher than the skin, generally in the face, hands. The causes of long 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 pigment mother cells will become very active. 2) Hormonal imbalance: The female hormone estrogen contained in birth control pills will stimulate the secretion of mellanin cells and form uneven spots. The spots formed by birth control pills will stop after the interruption of taking the pills, 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 you need to pay more attention to them. 3) Slow metabolism: spots will appear when the metabolism of liver is not normal or when the function of ovaries is reduced. The pigmentation problem is aggravated because of 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 who have 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. 2. External factors 1) UV ray: When irradiating UV ray, 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 the 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: The skin becomes sensitive due to strong cleaning habits, 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 an excess of pigment, there are 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.