Itchy red bumps on a three-year-old child may be prickly heat, insect bite dermatitis, allergic dermatitis and other causes, through open windows and ventilation, medication, reduce exposure to allergens will improve the symptoms. 1. prickly heat: three-year-old children in a long time in the humid and hot environment, may be generated in the skin surface of some red isolated or scattered red pimples, accompanied by obvious itching symptoms, choose to open the windows and ventilation of the living environment, to ensure that the house cool and dry, and apply glycerine lotion will improve the symptoms. 2. insect bite dermatitis: three-year-old children are often mosquitoes, fleas and other insect bites, the body will grow red bumps with itching discomfort, localized application of damphenol ointment and other medications, severe symptoms of taking cetirizine drops and other anti-allergy drugs. 3. Allergic dermatitis: three-year-old children in the case of unknowing contact with pollen, mites, seafood, milk and other allergic substances, can cause skin allergic reactions, red bumps with itching and other discomfort, you can go to the hospital to identify allergens, and try to avoid re-exposure to allergens in the future, the use of anti-allergy medication under the guidance of the doctor, such as cetirizine drops, and other anti-allergy medication. Three-year-old children with red bumps itchy body to go to the hospital to check the cause, the above drugs need to be used under the guidance of a doctor.