In the hot summer, the sun is in the sky, no matter we travel to the mountains or go shopping, we will be bathed in the sun for a longer time. Nature’s bright sunlight not only makes people happy, but also promotes the body’s metabolism, improves the immunity of the body, and prevents the occurrence of diseases. In terms of skin, proper sun exposure can increase sweat gland secretion, dilate blood vessels, promote the synthesis of vitamin D3, and bronze skin can beautify one’s appearance and make one look fit. Ultraviolet light accounts for only a small part of sunlight, but has a strong biological effect, and the effect of sunlight on human health is closely related to the ultraviolet light in it. In this topic, we will talk about UV radiation and skin health. First, the general characteristics of ultraviolet radiation in life, including natural and artificial sources, the sun is the most important source of natural ultraviolet radiation, the Earth’s surface sunlight consists of 3% ultraviolet radiation, 37% visible light, 60% infrared radiation and a small amount of X-rays, while artificial ultraviolet is mainly from medical and industrial use of ultraviolet lamps. According to the differences in biological effects, ultraviolet radiation can be divided into three different wavelengths: long-wave ultraviolet (UVA), medium-wave ultraviolet (UVB), and short-wave ultraviolet (UVC). UVA, also known as the black light area, can induce fluorescence from many substances; the largest amount of UVA reaches the earth’s surface, about 20 to 100 times that of UVB, but the energy of UVA is low and is generally not absorbed directly by biological macromolecules such as DNA UVB, also known as the skin erythematous zone, its wavelength is just near the absorption peak of DNA and protein, which can directly cause DNA and protein damage; UVC, also known as the sterilization zone, although its energy is the highest, but generally absorbed by the ozone layer in the atmosphere, will not cause biological effects on Earth. Second, a brief history of ultraviolet radiation for skin diseases Perhaps coincidentally, nucleic acids and proteins, the most basic and important substances that constitute life, have absorption peaks at wavelengths of 260nm and 278nm, respectively, which happens to be the wavelength range of ultraviolet radiation. Ultraviolet radiation is an important driving force for the origin and evolution of living things on earth, and plays an important role in maintaining human health and the prevention and treatment of many diseases. Whether in the West or in the East, in ancient times or in modern times, people regard sunlight as the light of hope for human life and health. Human beings have recognized the important role of ultraviolet radiation in sunlight for their own health since very early times. In ancient Greece, Rome and Egypt, doctors worshipped the healing effect of sunlight and used sunbathing to treat certain diseases. The Greek Hippocrates, who is considered the originator of light therapy, set up a clinic on the island of Kes to treat patients with skin diseases by sunbathing, while the Roman solarium of the same era also enjoyed great popularity, and the Danish physician Niels Fenschen won the 1903 Nobel Prize in medicine for using artificial ultraviolet light to cure patients with common lupus and skin tuberculosis. Ultraviolet radiation therapy was introduced to China in the 1950s and 1960s, but was gradually discontinued in the 1970s due to the low technical content and the harmful components of the light. In the eighties there were some improvements, and again accepted by some people, but there are still some problems. Into the nineties, due to advances in filtering technology, researchers developed narrow-spectrum medium-wave UVB (narrowband UVB, NB-UVB) and narrow-spectrum long-wave UVB (UVA1) lamps that emit only the most biologically active wavelengths of about 310nm in the UV spectrum by filtering out the larger bands of side effects in the UV spectrum, thus making This ancient treatment method has taken on a new luster by optimizing the efficacy of UVB irradiation therapy while minimizing its side effects. At present, in many European and American countries, narrow-spectrum UV irradiation therapy has become one of the preferred methods for the treatment of psoriasis, vitiligo, atopic dermatitis, pityriasis rosea and other skin diseases, and has also achieved good results in the treatment of eczema, seborrheic dermatitis, lichen planus, polymorphic heliotrope, nodular itchy rash and other skin diseases. Third, ultraviolet radiation and psoriasis commonly known as “psoriasis”, is a common disease in dermatology, generally divided into four types: common, pustular, arthritic and erythrodermic. It is characterized by white scaly erythematous plaques, itching and easy recurrence. It can occur all over the body, but is more common on the extremities, especially the elbows and knees, as well as on the scalp and lumbosacral area. In general, psoriasis does not seriously affect the patient’s general health and is not contagious, but because it can seriously affect the appearance of the skin and is prone to recurring episodes, it causes a lot of inconvenience to the patient’s life as a result of great psychological pressure, which may result in anxiety or a pessimistic and negative state of mind. At present, there are many ways to treat psoriasis, exaggerating a little, almost all the drugs on the pharmacopoeia have been used to treat psoriasis, but unfortunately there is no special therapy to cure psoriasis, the existing various therapies can only achieve the recent effect, can not prevent recurrence. Therefore, in the treatment of psoriasis, the first thing is to have a more comprehensive understanding of psoriasis, do not unilaterally pursue a cure, and avoid seeking medical help in an emergency, because some drugs that have been used for the treatment of psoriasis, such as hormones, arsenic, anti-tumor drugs, etc., although they can have an immediate effect, but may induce extremely serious side effects and make future treatment more difficult, therefore, psoriasis treatment, safe and effective methods are The first choice. At present, “green treatment” is advocated in psoriasis treatment, which includes phototherapy, hydrotherapy, mud therapy and psychotherapy. Phototherapy includes ultraviolet radiation therapy and photochemotherapy, and photochemotherapy uses long-wave ultraviolet light, which is less used at present because it requires oral or topical application of photosensitive substances and has greater side effects and may cause skin cancer and cataract; ultraviolet radiation therapy mainly uses medium-wave ultraviolet light, which can be used alone, or topical application of tar-like drugs plus ultraviolet radiation, or hydrotherapy (Godckerman triple therapy). Narrow-spectrum medium-wave UV irradiation has been successfully reported as early as the 1980s for the treatment of psoriasis, and in recent years it has become a safe and effective conventional means for the treatment of psoriasis in Europe and the United States. In 2002, we introduced a whole-body narrow-spectrum medium-wave ultraviolet therapy instrument produced in the United States, and this year, we purchased a localized domestic narrow-spectrum medium-wave ultraviolet therapy instrument, and in nearly 1,000 cases of psoriasis treatment observation, we found that narrow-spectrum medium-wave ultraviolet therapy for common psoriasis has the characteristics of good efficacy, few side effects, long maintenance time of efficacy and high acceptance by doctors and patients. Narrow-spectrum medium-wave ultraviolet irradiation is generally used to treat psoriasis once every two days for a few tens of seconds to a few minutes each time, and 10-15 times in a course of treatment. 90% of patients can completely clear their skin lesions after completing a course of treatment, and topical application of tar-like drugs can further improve its efficacy. If the disease is seasonal (generally prone to recurrence in winter), narrow-spectrum medium-wave UV irradiation before the change of season can prevent its recurrence or reduce its recurrence. In addition, UV irradiation is not suitable for severe pustular psoriasis, for erythrodermic type and arthritic type, other therapeutic drugs must be taken orally at the same time. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. The practice for many years proves that UV irradiation is one of the safest and effective methods to treat vitiligo, UV irradiation can not only promote melanogenesis, accelerate the transfer of melanin from melanocytes to the epidermal layers to deepen the skin tone, but more importantly, UV radiation can clear the pathological T lymphocytes in the skin lesions, so that the pigment cells can be restored to normal. Foreign scholars used narrow-spectrum ultraviolet treatment on 51 cases of children’s pancytopenia vitiligo, and found that 53% of the children had more than 75% of the lesions recovered, 80% of the children’s lesions did not expand, and the side effects were very mild. Similar results were obtained in our treatment observation in the last two years, and we also found that the efficacy of topical application of photosensitizing drugs could be improved. The use of narrow-spectrum medium-wave ultraviolet radiation treatment vitiligo generally 2 to 3 days irradiation once, the course of treatment must generally reach more than 3 months, the longer up to 1 year. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of these things. It usually starts in childhood, and some of them can be extended into adulthood. The most typical symptoms are pruritus and dry skin, often resulting in extensive scratching and mossiness. Because of the recurrent course of atopic dermatitis, itching and dryness of the skin are severe and often cause anxiety in children and their parents. Topical symptomatic treatment requires anti-inflammatory, anti secondary infection and prevention of skin dryness. Topical moisturizers can prevent skin dryness and often bring unexpected results. For severe cases, local and systemic application of glucocorticoids, interferon-gamma, cyclosporine, etc. is often ineffective and often associated with serious side effects. Since the pathogenesis of atopic dermatitis is closely related to the infiltration of pathological T lymphocytes in the skin lesions, UV irradiation can also achieve good results by removing pathological T lymphocytes from the skin lesions. Foreign scholars applied narrow-spectrum long-wave ultraviolet (UVA1, wavelength 340-400nm) and 311nm narrow-spectrum medium-wave ultraviolet treatment of moderate to severe atopic dermatitis, 3-5 times a week, after 2-3 weeks of treatment, about 80% of patients more than 60% of the lesions were cleared, no recurrence was seen in 8 weeks of follow-up, and the side effects were mild. Although with the successful use of narrow-spectrum ultraviolet technology, ultraviolet radiation has become a popular treatment method for doctors and patients in the treatment of some difficult-to-treat and recurring skin diseases including psoriasis, vitiligo and atopic dermatitis, ultraviolet is a double-edged sword and the harm of ultraviolet radiation to human body has been recognized for a long time. Excessive ultraviolet radiation, especially the ultraviolet radiation in sunlight, can not only cause acute and chronic damage to the skin and eyes, but also have a damaging effect on the immune system because it includes more harmful wavelengths. With the increasing damage to the ozone layer in the atmosphere, the UV radiation on the earth’s surface has increased significantly, and the harmful effects of UV radiation are attracting more and more widespread attention. For example, ordinary people can receive strong sunlight exposure can cause acute sunburn, long-term sunlight exposure can cause chronic damage to the skin, making the skin appear rough skin, wrinkles, pigment disorders and other photoaging changes, may also induce skin tumors; and after contact or taking some photosensitive substances, ultraviolet radiation will cause photosensitive skin disease, at the same time, ultraviolet radiation will also make lupus erythematosus, chloasma, porphyria, etc. chloasma, porphyria, etc. in the disease recurrence or aggravation. Therefore, we should pay attention to UV protection when we go out, such as avoiding direct exposure to the sun from 10:00 a.m. to 3:00 p.m., using sunscreen, holding an umbrella or wearing a wide-brimmed hat, etc. For those UV-sensitive patients, they should avoid sun exposure as much as possible, wear light-colored long-sleeved tops and pants, hold an umbrella, wear dark glasses and use sunscreen, and avoid taking photosensitive drugs, etc.