Children with upper body fever and cold feet may be caused by factors such as insufficient blood supply to the extremities, autonomic disorders, and immature central nervous system development. 1. Insufficient blood supply to the extremities: Because the blood volume of the extremities is less than that of the internal organs, insufficient blood supply can lead to fever and cold feet in children’s upper body. 2. Autonomic disorders: Because the child’s nervous system is not yet fully developed, the autonomic nerves responsible for the management of vasodilatation and contraction are easily disorganized, when the fever, the small blood vessels at the end of the limbs are in a spasmodic contraction and cold. This leads to children’s upper body fever feet cold. 3. Immature central nervous system development: As the child’s central nervous system is not yet mature, the ability to regulate body temperature is relatively poor, if the ambient temperature is low, the child’s hands and feet for a long time exposed to the outside, there will be a child’s upper body fever feet cold. Children’s upper body fever feet cold, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.