Psoriasis phototherapy is currently a relatively safe treatment, but no treatment is 100% free of side effects, and neither is phototherapy. Just like we are safe in the sun, but too much sunlight can cause sunburn. But light therapy is very small and causes relatively little harm to the body. The side effects of phototherapy are: ① Sunburn, the main element that causes sunburn is ultraviolet light, phototherapy is a part of the ultraviolet light stripped out of the treatment of disease, if used too much too strong will cause local sunburn. So a very experienced doctor is needed to control the dosage of light. If sunburn occurs, it can also be gradually recovered. ②Pigmentation. Pigmentation (darkening of the skin) will occur after 1 to 2 sessions of phototherapy, and the skin will be significantly darker after 10 or more sessions, but the skin will return to normal color after a few months of stopping the light. I don’t think the darkening of the skin is a problem, rather it will look a bit healthier. In addition to these two points, narrow-spectrum UVB can also cause rough and dry skin after long-term exposure, and the rest of the long-term side effects are rare. Many people worry about whether they will get tumors from long-term phototherapy. Current studies on narrow-spectrum medium-wave UVB have shown that UVB phototherapy does not have an increased risk of inducing tumors. In contrast, PUVA treatment may increase the incidence of skin tumors, so PUVA treatment is being used less and less worldwide. What should I do if side effects occur? When side effects of phototherapy occur, they can be treated in different situations. In the case of acute sunburn caused by excessive light exposure, a cool shower or a cold compress can be applied topically. Some scholars believe that hot showers or hot compresses are effective. In addition, topical emollient creams or corticosteroids can reduce inflammation, and oral anti-inflammatory drugs can be taken in particularly severe cases, but do not take hormonal drugs. In general, acute sunburn is a transient injury that takes a few days or ten days to recover slowly. For tanning, no treatment is needed, and it will fade slowly with time. For dry skin after phototherapy, it is recommended that patients moisturize their skin with moisturizing creams and oils after exposure. What are the conditions to stop phototherapy? Phototherapy should be stopped when any of the following conditions occur (1) There is a more visible sunburn. ②Erythema reaction (red patches of skin), if the whole body is blistered, red, swollen and painful, you need to stop phototherapy immediately. You can only re-irradiate after a period of cessation. The dose of phototherapy should be reduced when re-irradiating. ③Eating photosensitive drugs or food, etc. (iv) Occurrence of the contraindications to phototherapy mentioned above. In addition, the use of phototherapy is not recommended when immunosuppression is applied. What is the cost of phototherapy treatment? Generally speaking, the cost of full body irradiation for full chamber treatment is$60 per session and$30 per session for local irradiation, which varies from hospital to hospital, but the cost of phototherapy can be reimbursed through medical insurance.