ultraviolet light therapy for psoriasis

Type:Uv phototherapy   Time:2019-01-16 22:06:13 Psoriasis is a common disease in the dermatology department. The patient presented with recurrent red patches of skin with silvery white scalys. The area can range from the tip size to the large piece to the general body. Because psoriasis is a chronic disease, it is easy to recurrent and there is no way to cure it. Patients are often very distressed. The treatment of psoriasis has also become an important topic in ancient and modern skin science. People have done a lot of exploration and research in this area, and many effective treatment methods have been summarized in modern times. Among them, the most commonly used are a variety of external preparations, such as hormonal drugs, retinoids, vitamin D derivatives, as well as tar, Enlin, keratin promoter and emollients. Oral medications, including immunosuppressants, retinoic acid, etc., can also be used in more severe cases. In addition to medical treatment, there are some physical means to effectively treat psoriasis, including phototherapy, hydrotherapy, and climate therapy. This article focuses on the most effective and currently the most widely used UV light therapy.

People have long discovered in life practice that sun exposure can improve health and cure diseases. In the sun component, the main therapeutic effect is ultraviolet light. Danish doctor Finson was the first medical scientist to use artificial ultraviolet light therapy to treat skin diseases. He received the Nobel Prize in Medicine and Physiology in 1903 for his pioneering contribution to the application of phototherapy to skin diseases. In 1925, the German doctor Gokman summed up the famous Geckman triple therapy, began to apply the ultraviolet light therapy to the treatment of psoriasis, and widely promoted, and achieved good therapeutic results.

With the advancement of science and technology, the emergence of new artificial light sources and the continuous exploration of psoriasis treatment methods, the method of phototherapy for psoriasis has also developed rapidly. To date, widely used phototherapy is mainly photochemotherapy (PUVA therapy) and narrow-spectrum UV-wave therapy (narrow-spectrum UVB therapy or 311 nm UVB therapy).

PUVA therapy has been widely used in the treatment of psoriasis in Europe and the United States since the 1970s. The specific method is: after oral or topical psoralen drugs (photosensitizers), the appropriate dose of long-wave ultraviolet radiation to the whole body or the patient's part. Both the dose and the dose of light should be determined according to the patient's condition and gradually increase the dose of light. It usually takes 2 to 4 times a week to treat, and most patients can be significantly improved after 1 to 2 months of treatment, or even completely remove the skin lesions.

The mechanism of PUVA therapy is to affect the replication of epidermal cell DNA and inhibit the excessive proliferation of skin cells in psoriasis by the synergistic action of photosensitizer and long-wave ultraviolet rays, thereby playing a therapeutic role. Because of the use of photosensitizers in PUVA therapy, patients should be protected from light during the day after treatment. Patients with oral photosensitizers also need to wear special UV-protective glasses to avoid damage to the skin and eyes caused by sunlight. Photosensitizers may affect fetal development, so PUVA therapy cannot be used in pregnant women. Children should be used with caution.

Ultraviolet light (UVB) can treat psoriasis by irradiation alone because it has higher energy than long-wave ultraviolet light. Scientists have found through comparison that the best UV-wave band for the treatment of psoriasis is near the 311 nm wavelength. Therefore, in 1988, Philips produced a narrow-spectrum UVB fluorescent tube with an emission wavelength of 311 nm, which became the best therapeutic light source. Since the development of narrow-spectrum UVB phototherapy, it has become a new and effective treatment method for psoriasis. The specific treatment method is: according to the patient's condition, select a certain initial dose, ultraviolet radiation to the patient's part or whole body, 2 to 4 times per week, gradually increase the dose during the treatment, usually after 5 to 10 treatments. The disease can be improved. After 1 to 2 months of treatment, most patients can be basically cured, and even the skin lesions are completely removed. There is mild pigmentation in the affected area after treatment, but it can resolve in a short period of time.

The mechanism of narrow-spectrum UVB treatment of psoriasis mainly has the following two aspects: 1. UVB irradiation inhibits the proliferation of lymphocytes, reduces the number of inflammatory cells, and reduces the inflammatory response in patients with psoriasis. 2. Inhibiting T helper cell-mediated immune responses to treat psoriasis associated with the response.

Evaluation by scientific contrast experiments found that narrow-spectrum UVB treatment is roughly equivalent to PUVA therapy in terms of efficacy. However, the narrow-spectrum UVB therapy has the following advantages over the latter: 1. It is not necessary to take the drug before the light, and the treatment is quick and convenient, and the treatment time is short. 2, do not need to take photosensitizers, no related systemic adverse reactions such as nausea and vomiting, and avoid the limitations of photosensitizers on the indications, the safety of treatment for pregnant women and children increased. 3. No strict anti-light and eye protection is required after treatment. Because of these advantages, narrow-spectrum UVB treatment has been more and more widely carried out in recent years, and there is even a tendency to gradually replace PUAV therapy.

In general, UV phototherapy has the following advantages in treating psoriasis:

1. The curative effect is exact and the efficiency is high. The application of phototherapy in the world has been used to treat psoriasis for decades. A large number of clinical data indicate that PUVA and narrow-spectrum UVB have very positive effects. Most patients with psoriasis can be treated with appropriate phototherapy. Satisfactory efficacy.

2, the relevant equipment is perfect, can adapt to a variety of sick conditions. Due to the development of technology, we have a variety of artificial ultraviolet light sources, a variety of different specifications of ultraviolet light therapy equipment. Various types of irradiation equipment can be selected for different patients and different diseased parts, and from local patients to systemic diseases and even individual parts, the corresponding equipment can be used for treatment.

3, treatment is quick and convenient, no hospitalization. Phototherapy is generally carried out in the daytime treatment center of the hospital dermatology department. Patients can flexibly arrange treatment time according to their own situation and doctor's advice, only a few minutes to tens of minutes each time. Therefore, it has less impact on normal life work.

4, good safety, no rebound after stopping treatment. As phototherapy methods take longer and more experience, their safety is being widely confirmed. The dermatology community now recognizes that phototherapy is a safer treatment (see below for side effects on phototherapy). Most patients get a longer remission period after treatment. Patients can choose appropriate maintenance treatment after treatment to reduce and delay recurrence.

5, the cost of treatment is not high. At present, the core components of phototherapy equipment cannot be produced in China, so the price of phototherapy related equipment is still relatively expensive. However, the consumption of equipment components is less in the treatment process, so the cost of phototherapy treatment is not very high, considering the high efficiency of treatment, compared with other therapies, the author believes that phototherapy is a more economical treatment.