Freckles, the “face problem” that women are afraid of, do you know it? I. Etiology Freckles are autosomal dominant diseases. The tyrosinase activity in the melanocytes of freckled skin increases, and after the exposure to sunlight, X-rays and ultraviolet rays, a large amount of melanin is produced and freckles are formed. It has been proposed that freckles are the result of a small self-limiting mutated melanocyte strain. This mutation is associated with sunlight. II. Clinical manifestations Freckles do not appear at birth, but usually appear in early childhood. More females than males. They often occur on exposed areas, especially the face, especially the nose and cheeks are most common, and rarely on the trunk. The lesions are 3-5 mm in diameter, round, oval and polygonal with irregular edges, light brown to dark brown spots with clear boundaries, isolated but not fused, and can be sparsely and unevenly distributed. The number, size and color of freckles depend on the amount of sunlight absorbed and the tolerance of individuals to sunlight. According to the characteristics that the disease occurs in exposed areas, isolated and non-fused brown spots, aggravated by sunlight, it is easy to diagnose. Third, the treatment plan Avoid sun exposure, available sunscreen (choose SPF15 or more is good, when outdoor can choose high SPF products). Traditional treatment methods include freezing, chemical peeling, electrocautery, and topical application of various spot removal drugs, which are less effective and have more side effects, and have been basically eliminated. At present, the best treatment method is laser treatment. Q-switched laser treatment with wavelengths of 532nm, 694nm and 755nm can be used, and most people can be removed after 1-2 treatments. At present, some people also choose intense pulse light to treat freckles, which is slightly less effective than laser, but because of its larger spot, it is suitable for denser freckles. Precautions after treatment 1. Reduce erythema, edema and exudation After laser surgery, cold compress should be applied according to the immediate performance of the skin, usually 15-30 minutes, the time of cold compress depends on the intensity of the treatment, the personal experience of the physician and the needs of the patient. 2, prevent infection, reduce inflammatory response, promote wound healing Treatment area such as epidermis is not broken, can be washed with warm water 24 hours after treatment, but do not rub. If the epidermis is broken, to prevent trauma infection, avoid contact with water for 4-7 days locally, and apply antibiotic ointment topically. If there is a scab, do not use your hands to pick it off in advance, and wait for it to fall off naturally. 3.Avoid sun exposure Since pigmentation is easily caused after laser surgery, make sure to use sunscreen products with high safety and good sun protection effect (SPF＞30, PA++～+++ products). In addition to choosing to use sunscreen, wear a sun hat, cotton long-sleeved tops and long pants, and a sunshade when going out. Avoid going out at the time of the day when the sun is most intense, such as 10:00 am to 4:00 pm. 4. Diet The role of diet in skin repair cannot be ignored. Protein, fat and sugar are the necessary nutrients for the skin, vitamins and trace elements can affect the normal metabolism and physiological functions of the skin, such as: B vitamins, folic acid can increase pigmentation; vitamin C, vitamin A can make pigmentation decreases; certain trace elements copper ions can promote melanin production. Therefore, large area laser surgery, especially after the more invasive laser treatment should avoid eating food containing copper, B vitamins, and eat less spicy food. V. Whether there is recurrence after laser treatment Freckles are autosomal dominant diseases, after laser treatment, most of the patients will have scabs falling off in 7-10 days after the operation, and the local color will be pink, and the color will gradually return to normal in 1 month. A small number of patients will have hyperpigmentation, but it will gradually fade away in a few months. After the freckles are cured, some people will have recurrence, but the time of recurrence varies greatly among individuals, usually from one year to several years, and the freckles will gradually increase, or the color will gradually deepen. At this time, laser treatment can be used again.