The sudden appearance of a bunch of very itchy bags on the body may be caused by eczema, urticaria, insect bite dermatitis and other factors, which can be treated with topical and oral medications. 1. Eczema: a chronic itchy skin disease, the rash is symmetrically distributed, can appear in any part of the body, mostly accompanied by obvious itching. It can be treated with topical glucocorticoid ointment such as mometasone furoate cream and oral antihistamine such as loratadine. 2. Urticaria: the main clinical manifestation is the wind and angioedema, mostly accompanied by obvious itching. If the itching is obvious, you can use glycerine lotion or mometasone furoate cream and other drugs to stop itching, and oral antihistamines such as cetirizine, loratadine and other drugs. 3. Insect bite dermatitis: mostly related to mosquito bites, need to maintain local environmental hygiene, and regularly kill mosquitoes, followed by symptomatic treatment, such as external glycerine lotion, zinc oxide ointment to stop itching. When the itching is obvious, can be combined with oral chlorpheniramine maleate and other drugs. The body suddenly appeared a bunch of very itchy bag, you should promptly go to the hospital, improve the relevant examination to clarify the cause of the disease, under the guidance of the doctor symptomatic treatment, to avoid unauthorized use of drugs. Drugs need to be used in accordance with medical advice.