1.What is freckle? Freckles are a kind of brown dotted pigmentation spots commonly found on the face, and sunlight can aggravate and promote the disease. 2.Does freckles run in families? Freckles have a certain tendency to be inherited, and it is a polygenic disease, but some families show autosomal dominant inheritance. There are some syndromes with freckles, which can be autosomal dominant or autosomal recessive. 3.What are the manifestations of freckles? Most of the patients are female, most of them have onset at young age, and they usually appear on the face, especially on the nose and cheeks. The damage is pinhead to rice-grain size, light brown to dark brown spots, varying in size and variable in number. There are no conscious symptoms. Generally speaking, it is heavier in spring and summer than in autumn and winter. 4.Why should I pay more attention to sun protection if I have freckles? It is because after receiving sunlight, X-rays and ultraviolet radiation, the melanosomes in the epidermis become oxidized rapidly and the rash deepens, becomes bigger and increases. For example, the incidence and severity of freckles in areas with high altitude and strong sunlight (such as Xichang, Qinghai, etc.) are significantly higher than those with weaker sunlight (such as Beijing). 5.How to treat freckles? First of all, avoiding sunlight and applying sunscreen are important for freckle treatment. Sunscreen should be used with SPF20, PA++ or above. Secondly, the treatments for freckles include medication, cryotherapy and laser treatment. Among these treatments, laser treatment has the most certain effect and higher cost. Medication: The use of 3% hydrogen peroxide solution and hydroquinone cream can get temporary effect. Liquid nitrogen freezing: Caution is needed as it may cause hypopigmentation or even scarring. Laser treatment for freckles: 510nm, 532nm, 694nm, 755nm Q-switched laser treatment can be used. However, it cannot prevent recurrence. 6.What lasers are available to treat freckles? 1) Red light and near infrared light laser: including Q-switched ruby laser (694nm), Q-switched emerald laser (755nm), the above two lasers can effectively remove freckles in 1-2 times. At present, Q-switched 755nm emerald laser is the preferred method for freckle treatment. 2) Frequency doubled Nd-YAG laser: 532nm wavelength, repeat treatment interval 6-8 weeks. The immediate response to treatment is a grayish-white change in the tissue. 3) Quasi-continuous wave copper vapor laser (511nm) and krypton laser (520-530nm): Due to the continuous laser, skin texture change may occur. 4) Pulsed Intense Light (IPL): i.e. photorejuvenation, which is not a laser, is slightly less effective than laser and relatively more prone to recurrence. However, it is relatively inexpensive and has light reactions such as redness, swelling and crusting after treatment. Repeat treatment interval is 2-4 weeks. 7. What are the precautions for laser treatment of freckles? Firstly, skin care products and cosmetics should be removed before treatment to avoid their influence on laser treatment; secondly, patients need to understand that due to the characteristics of yellow people, there may be a certain degree of pigmentation, so the first treatment can start with a small area (generally speaking, 755nm laser pigmentation is less likely); regular follow-up after treatment; sun protection and avoiding light as much as possible after treatment; attention to prevention of infection; recurrence is still possible after cure.