Solar dermatitis, also known as “polymorphic sun rash,” is a photosensitive dermatosis that commonly affects young and middle-aged women and is common in spring and summer. The disease often develops in the spring after the first exposure to strong sunlight, and manifests itself as a rash of erythema, papules, pemphigoid and blisters on the face, neck, forearm extensor, back of the hands and other exposed areas. The lesions are closely related to sun exposure, and most of them are significantly aggravated and itchy after exposure. The rash often recurs after proper avoidance of light. Over time, mossy changes and increased pigmentation may occur. The rash usually decreases after autumn and recurs in the following spring, and can last for many years. The incubation period is determined by the intensity of sunlight, the duration of sun exposure and the sensitivity of the individual’s skin. The incubation period depends on the intensity of sunlight, the duration of sun exposure and the sensitivity of the individual’s skin. 2. The basic damage is a large red patch with edematous, sharp edges, and severe blistering and burning pain. Anti-allergic treatment is effective. 3.The lesions mainly occur on the face, neck, hands, forearms and other exposed areas. 4. Generally, there are no systemic symptoms, but when the damage is extensive, it can be accompanied by headache or fever. The treatment of solar dermatitis mainly adopts local topical drug therapy, based on the principle of anti-allergy and pain relief. Generally, topical application of glyburide lotion or oscillating lotion is sufficient. If the lesions are severe, local ice is used every two to three hours wet compress for a few minutes until the acute symptoms subside, and later can be used externally corticosteroid cream, which has the effect of significantly reducing local redness, swelling and heat pain; severe itching, plus antihistamines, such as fexofenadine tablets; systemic symptoms of oral antihistamines and a small amount of sedatives, and give rehydration and other symptomatic treatment, especially important is to prevent re-exposure to the sun. The prevention of solar dermatitis Reduce the time of exposure to strong sunlight and often participate in outdoor activities to enhance the skin’s ability to tolerate sunlight. Reduce the time spent outside: the strongest light of the day is from 10am to 2pm, so you should reduce your exposure and take shade or use sunscreen when you go out. Strengthen the protection of exposed parts, such as: apply sunscreen on exposed parts or wear long-sleeved clothes; wear a broad-brimmed hat or hold an anti-UV sunshade when the sun is full; 3 Avoid using taking photosensitive drugs and foods, such as: 8-methoxypsoralen, tetracycline, ashwagandha, acacia, etc.