Sunburn, also known as sun spots or solardermatitis, is an acute inflammatory reaction of the skin to sun exposure. The skin receives more than the tolerated amount of ultraviolet light, mainly medium wave ultraviolet (UVB). After overexposure of the skin to UVB, proteins and nucleic acids in the cells absorb large amounts of UVB to produce a complex series of photobiochemical reactions (which can be crudely interpreted as the body’s cells being burned by sunlight) and locally produce a variety of active substances, such as histamine and prostaglandins. These substances diffuse into the dermis (reach the sunburned skin locally) and cause inflammatory reactions such as vasodilation (redness and swelling of a large area) and cellular infiltration, thus causing inflammatory reactions in the epidermis and dermis. The onset of the disease varies depending on the intensity of sunlight, the duration of exposure to sunlight (even a second of strong light can not hurt people) and individual skin sensitivity (black friends see this, can not help but laugh out loud, revealing a mouthful of white teeth). Long-term indoor workers suddenly short-term outdoor labor (a long time without fighting with ultraviolet rays, suddenly a fierce will not be able to eat well), or long-distance march in the field (to carry out the task is important, tanning sunburn that is nothing) or a long time after sunbathing (warm sleep over) prone to occur, light-skinned people prone to hair (black people are the descendants of the sun, the sun sheltered them), in the mountains, snow-capped mountains, beaches, etc. ( Qinghai-Tibet Plateau, Maldives is not leaving you deep memories?) Environmental susceptibility, late spring and summer (these two seasons people are wearing simple clothes out activities). Mostly occurs within 2-12 hours after exposure to sunlight. The lesions are usually confined to the exposed area. The initial lesions are bright red to scarlet edematous spots with sharp edges, or blisters in severe cases. Localized burning pain is felt. After a few days, the erythema and edema subside, followed by desquamation (fading of dead skin) and temporary hyperpigmentation (the white and tender skin is lost and turns into a black girl). Emphasis on prevention, avoid exposure to the sun, before going out in the hot sun can be used in the exposed parts of the external physical shading agent (sunscreen la), according to the individual skin color type to choose the sun protection index of the shading agent (preferably 50 times, and every 1-2 hours to make up, sweating washed away a lot). Treatment is simple, with the principle of anti-inflammatory, soothing and pain relief. Topical stove glycolic lotion can be used, and in severe cases, wet compresses of ice milk can be used. Those with systemic symptoms can take oral antihistamines, non-steroidal anti-inflammatory drugs, and in severe cases, glucocorticoids. The direct introduction of vitamin C, tranexamic acid, glutathione and other drugs from the skin with instruments can also play a certain anti-darkening effect.