Itchy red rashes on the body may be caused by contact dermatitis, eczema, hives and other diseases. 1. Contact dermatitis: contact dermatitis is due to skin contact with certain allergens, causing contact with the skin and the skin outside the contact area, the inflammatory reaction. Patients will appear in the skin erythema, edema, papules, blisters, itching and other symptoms. 2. Eczema: the cause of eczema is not yet clear, may be genetic, immune abnormalities, hormone level changes, endocrine abnormalities and other factors. Patients will have symptoms such as pimples, papules, erythema, and intense itching. 3. Urticaria: Urticaria may be caused by drug allergy, infection, autoimmunity, physical stimulation and other factors. Patients will appear edematous plaques, red wind, itching and other symptoms, manifested as itchy red rashes on the body, scratching can be a large wind. There are many reasons (such as prickly heat, etc.) that lead to itchy red rashes, so it is recommended that patients find out the cause of the disease in a timely manner and avoid self-medication.