If you get hives when you are hot, you may have heat urticaria, also called cholinergic urticaria. It may be related to the environment, diet and spirit. 1. Environment: If the environment is too hot, resulting in increased skin temperature and body heat, which increases the release of acetylcholine, hives may occur. 2. Diet: If you drink too hot drinks, spicy and stimulating foods, and alcoholic beverages, the body’s internal temperature will rise rapidly and acetylcholine will act on mast cells, resulting in hives. 3. Spirit: If the spirit is in a high degree of tension or excitement, it will make the brain temperature regulation center in the state of excitement, the release of acetylcholine increased, hives may appear. There will be pimples with redness, intense itching or burning sensation when hives appear when you are hot, you should avoid scratching, and it is recommended to go to the hospital in time and standardize the treatment under the doctor’s diagnosis.