Usually, itchy body when it is hot may be caused by summer dermatitis and hives, sweating and other conditions. 1. Summer dermatitis: a seasonal, inflammatory skin disease caused by summer heat. It is characterized by large red patches of skin with pimples and papules, often itchy, and the lesions may subside soon after the weather cools down. 2. Urticaria: It is caused by a variety of foods, drugs, exercise and other reasons that lead to the temporary expansion of small blood vessels in the skin and mucous membrane and increased permeability, local edema occurs. After exercise, the body becomes hot, and there are lumpy elevations on the skin of different sizes, bright red or pale white, accompanied by obvious itching. 3. Sweating: sweat, oil and other substances can appear on the skin after sweating, easy to breed bacteria, can also appear hot when the body itchy phenomenon. In addition, hot body itchy or accompanied by other discomfort patients, it is recommended to go to the hospital in a timely manner, in accordance with the doctor’s instructions for treatment, to avoid delaying the condition.