Itchy skin bumps after sun exposure may be suffering from photosensitive dermatitis, which is a disease sensitive to ultraviolet rays, ultraviolet irradiation will cause its own immune response, and then produce pimples, blisters with itching, etc., occurring in the face, neck, chest and back, arms and upper limbs, and other exposed parts of the body. The treatment of the disease is based on prevention, which includes avoiding overexposure to the sun, wearing protective clothing, applying sunscreen, etc. Reducing the skin’s exposure to ultraviolet rays can minimize the onset of photosensitive dermatitis. The treatment of the disease is as follows: 1. Good sun protection, avoid ultraviolet radiation, and discontinue the use of chemicals or drugs that cause photosensitivity, to reduce the exposure to the source of irritation can relieve the symptoms. 2. Under the guidance of a doctor, local application of glycerine lotion to relieve itching, oral antihistamines or glucocorticoid drugs can effectively slow down the inflammatory reaction, and then reduce the skin redness, swelling, itching and pain and other discomforts. 3. Ultraviolet light therapy in the hospital, with the right amount of ultraviolet light irradiation of the skin, can help regulate the immune system. 4. Omalizumab therapy, which is mainly for asthma patients, is also effective in reducing allergic reactions in patients with severe photosensitive dermatitis. It is recommended that patients with itchy skin bumps after sun exposure go to the dermatology department of the regular hospital in a timely manner to clarify the cause of the disease and standardize the use of medication under the guidance of the doctor.