Redness and itching of the skin after being exposed to the sun may be caused by polymorphic sun rash, which can be improved by medication, strengthening sun protection measures and preventive phototherapy. 1. Medication: polymorphic sun rash may be related to hypersensitivity reaction in the body, and patients with relatively mild symptoms can apply topical tacrolimus ointment, pimecrolimus cream, dexamethasone ointment and other ointments to help anti-inflammatory and anti-allergy treatment. On the basis of topical medication, taking hydroxychloroquine, niacinamide and other drugs is effective for some patients, and severe cases also need to take oral prednisone, cyclosporine and other drugs at the same time. 2. Strengthen sun protection measures: ultraviolet radiation will make the patient’s skin redness, itching and other symptoms further aggravated, so patients should pay attention to avoid exposure to the sun, strengthen the sun protection measures, such as going out using hats, masks, umbrellas, sunglasses, and other physical sunscreen products, to help isolate the ultraviolet radiation damage. On this basis, you can also use mild sunscreen, sunscreen spray and other chemical sunscreen products to further enhance the effect of sun protection. 3. Preventive phototherapy: For people with overly sensitive skin, you can also pay attention to the skin before the onset of the season to gradually increase the appropriate sun exposure, and if necessary, preventive phototherapy on the skin to help improve the skin’s ability to tolerate light, thus helping patients to reduce the frequency of polymorphic sunburn rash. It should be noted that the redness and itchiness of the skin after being exposed to the sun should be promptly consulted, and the above treatments should be carried out under the guidance of a physician to avoid the occurrence of adverse reactions.