Sun allergy can cause solar dermatitis or sunburn, which mainly appears as large edematous erythema, on top of which small papules and small blisters can be seen, some of which can fuse into large blisters, and are accompanied by itching and stinging pain. The clinical treatment requires wet application of 2% boric acid solution twice a day for 20 minutes, or cold wet application of decoction of fresh amaranth, honeysuckle, forsythia and cypress twice a day for 20 minutes, to clear heat and detoxify, cool blood and relieve pain. After the above wet compresses can be applied topically with Denide ointment 1:1 with zinc oxide ointment of boric acid. For large blisters, a sterile syringe should be used to draw out the herpes fluid, and then apply fusidic acid ointment for treatment afterwards. Alcoholic beverages need to be avoided during the treatment period, and spicy and irritating foods need to be avoided. Oral treatment with anti-allergy medication should be intensified, and oral levocetirizine hydrochloride capsules can be taken, one capsule every night.