Repeated red bumps on the body are very itchy, may be caused by atopic dermatitis, eczema, urticaria, pigmented itchy rash. 1. Atopic dermatitis: the cause of the disease is not clear, and is related to genetic, immune, environmental and other factors, can be manifested as erythema on the basis of pimples, papules, with itching. 2. Eczema: related to a variety of internal and external factors, lesions are mainly pimples, papules with itching, redness and swelling and other symptoms. 3. Urticaria: most of the urticaria can not find the exact cause, usually related to food, drugs, infections and other factors, which can lead to the appearance of the skin, erythema with itching. 4. Pigmented itchy rash: pigmented itchy rash may be related to contact allergy, mechanical stimulation and other factors, resulting in red or reddish-brown papules, papules with itching. Repeated itchy red bumps on the body, there may be other reasons, it is recommended that the patient promptly to the hospital dermatology department.