When a child has a fever of 39℃, it should be considered as high fever. Feet and limbs are cold. The reason is that the body temperature continues to rise because the heat in the body does not dissipate and the peripheral circulation is poor. At this time, you should pay attention to keeping warm, mainly the palms of your hands and feet. You can soak the palms of your hands and feet in warm water and scrub them repeatedly with a towel. If necessary, you can rub the whole body, especially in the armpits, groin and under the neck, to play a physical cooling effect. It can also ensure the peripheral circulation of the extremities, promote heat dissipation, accelerate the fall of body temperature, test the blood routine at any time, and treat the cause of the disease.