The appearance of cold for a while and hot for a while is a manifestation of fever, which is usually often caused by various bacterial and viral infections. In the stage of rising body temperature, pyrogen acts on the thermoregulatory center to shift the thermoregulatory point upward. In the stage of rising body temperature, skeletal muscle tremor, skin vascular contraction produces more heat to make the body temperature rise, and in the process of rising body temperature, skeletal muscle tremor and contraction, the patient will have chills and fear of cold feeling. If the body temperature rises to a certain stage and reaches a new regulating point, the patient will experience fever and fear of heat. At this time, the body temperature center will again distribute heat through vasodilatation, so that the body temperature does not continue to rise, and at this time, the skin of touching the limbs will be hot. Therefore, fever is a common phenomenon in the process of fever, if the body temperature is too high or the patient feels obviously uncomfortable, you can follow the doctor’s instructions to improve the symptoms of oral antipyretic drugs, such as ibuprofen, etc.; more important is to seek medical treatment in time to deal with the cause of the disease.