Itchy red bags all over the body may be insect bite dermatitis, body lice disease, urticaria and so on. 1. Insect bite dermatitis: if it is in summer, there are outdoor activities, this situation should be considered the same dermatitis, mainly because after the insect bite, the poisonous juice will stimulate the skin, so that the skin will appear allergic and inflammatory reaction, there will be different degrees of itching. 2. Body lice: Body lice can be found in underwear, collars, underpants, crotch, head scarf, bedding and other parts of the body, and will bite all over the body, resulting in erythema, pimples or bumps all over the body, accompanied by itching. 3. Urticaria: Most patients can not find the exact cause, common causes include food, infection, drugs, respiratory inhalants and skin contacts. Patients are often suddenly self-conscious of itchy skin, soon appeared in the itchy parts of the size of the red wind,. Many diseases can cause itchy red bumps all over the body. Seek medical attention as soon as possible, make a comprehensive diagnosis based on clinical symptoms and examination results, and treat promptly.