Red rashes on the body in hot weather may be related to eczema, infantile emergency rash or hives and other diseases. 1. Eczema: its occurrence should be considered in relation to food (such as fish, shrimp), pollen, living environment (such as heat, dryness) and psychoneurological factors, etc., which can appear in many parts of the body, red spots, pimples, causing intense itching symptoms. 2. Early Childhood Acute Rash: It is an acute rash dermatosis that occurs in infants and young children infected with human herpes virus, the child suddenly develops a fever that lasts for 2 to 5 days and then drops abruptly, and the body will appear with rose-colored papules when the fever symptoms are about to recover or have returned to normal. 3. Urticaria: the causes of this disease are many, in the heat of the day, can be associated with physical stimuli (heat, sunlight, etc.), skin contact irritants, such as solar urticaria, sun exposure can appear a few minutes after the red spots and wind, causing itching and pain, but can subside on their own. When a rash appears on the body, it is recommended to consult a doctor to clarify the cause of the rash and then give targeted treatment.