Not every photodynamic therapy, will cause local skin ulceration and peeling, the emergence of adverse reactions, usually with the photodynamic therapy irradiation site, scope, dose has a certain relationship.1, the treatment site: photodynamic therapy in the clinical application of the wider, can be used to treat facial acne, flat warts, but also for the treatment of warts, so photodynamic irradiation of the site can be the face, the hands or the vulva and other parts of the body. Vulva and other parts of the body. When the vulva is treated with photodynamic therapy, skin ulceration and peeling will be more likely to occur due to the humidity. Face, hands or other dry skin parts, the phenomenon of ulceration and desquamation will be relatively light, or may not occur; 2, irradiation range: general lesions of the larger the scope of damage, photodynamic therapy irradiation of the larger the scope of the more likely to lead to the emergence of ulceration and desquamation of the skin; 3, irradiation dosage: if the photodynamic therapy, do not grasp the irradiation dose, may cause damage to the skin, resulting in localized ulceration and desquamation of the skin. Localized skin ulceration and peeling. Therefore, when receiving photodynamic therapy, follow the doctor’s instructions to ensure that the treatment area is dry and clean. If the photodynamic therapy irradiation is on the face, pay attention to sun protection, to reduce ultraviolet burns, if the irradiation is on the perineum, pay attention to the perineum clean. At the same time, patients need to pay attention to dietary restrictions, do not eat spicy stimulating foods, such as chili peppers, garlic, etc., and do not eat seafood and other easily allergic foods.