A mosquito bite and a large swollen bag appears, which is typical of insect bite dermatitis, which is an allergic disease. Insect bite dermatitis, also known as papular urticaria, is due to mosquito bites on the skin after the skin to mosquito secretions or venom of the allergic reaction, the formation of a patchy rash, papules, and accompanied by itching as the main features of the skin disease. Pemphigus urticaria mainly occurs in the exposed parts of the skin, and the onset of the summer and fall seasons. Symptoms can be relieved by topical application of anti-allergic and anti-itching medications, such as glycerite lotion and Denuded cream. In severe cases, oral antihistamines such as loratadine tablets can be given. The first step in the treatment of insect bite dermatitis is to avoid contact with mosquitoes, and when choosing medication, it is important to follow the doctor’s instructions.