Summer itself is a high season for skin diseases, and papular urticaria accounts for one-third of them. Outpatient clinics often encounter patients with red rashes all over their bodies, which itch so much that they even affect their work and sleep. It also affects the image, and women are therefore afraid to wear short sleeves and skirts. Most of the causes of papular urticaria are related to insect bites, such as mosquitoes, bedbugs, fleas, lice, mites, midges and other bites caused. Allergic reactions are often caused by mite bites on straw mats in summer. Individual quality of insect bites react differently. So the reaction also varies greatly. Even if a couple sleeps in the same bed, a person will have a rash all over the body and scratch itchy, but a person does not react at all. Insect bites inject saliva into the skin and cause the disease in people who are allergic to these substances. This is a delayed allergic reaction, and the bite after sensitization contributes to the development of the rash. Repeated bites can produce desensitization, so the disease gradually decreases with age. However, after a change of environment, the reaction to local insects that have not been in contact with it can be very severe, which is called “uncomfortable with the soil”. Clinical manifestations of papular urticaria The lesions are mostly on the trunk and extensor surfaces of the extremities. Cluster or scattered. They are slightly fusiform red lesions of green bean to peanut size, some may have pseudopods, often with small blisters at the top, and some become large, hemispherical, elevated, tense blisters with clear content and no surrounding redness soon after they occur. The rash is skin-colored or light red or light brown, and in some cases it is a hard, chestnut-sized papule that becomes swollen after scratching. Old and new rashes often coexist. In general, young children have significant redness and blisters, and often have severe itching that affects sleep. Scratching can cause secondary infection. The rash subsides after 1 to 2 weeks, leaving temporary hyperpigmentation, but a new rash can occur one after another, making the disease prolonged. The rash is often recurrent and usually has no systemic symptoms. Local lymph nodes are not enlarged. Papular urticaria differential diagnosis 1. Children’s itchy rash is a rash of rice grains to green beans mainly on the extremities, infiltration is obvious, mostly symmetrical distribution, scratches, blood crust, eczema, etc., often accompanied by lymph node enlargement. Chickenpox has papules, blisters, significant redness, rashes on the scalp and mucous membranes, some with dark brown scabs, mild itching, prodromal symptoms and mild systemic symptoms. 2. Urticaria is often accompanied by a wind-swept lesion, which often subsides within 24 hours. Based on the nature of the rash and the medical history, it is easily distinguished from aspergillosis and herpetic epidermolysis bullosa. Treatment of papular urticaria Internal antihistamines have been shown to be effective. Second-generation antihistamines such as cetirizine are commonly used. Topical application of 1% peppermint glyburide lotion (children should pay attention to the stimulation of drugs) and glucocorticoid ointment can stop itching and anti-inflammatory. If there is secondary infection, anti-infection treatment should be given, Chinese medicine can be used Jing Fang Tang or Yin Qiao San. The dermatophyllin application of our hospital is an effective medicine for the treatment of papular urticaria.