Sweating in children may be a normal physiological phenomenon, or it may be caused by vitamin D deficiency or hyperthyroidism. 1. Normal physiological phenomenon: in the case of hot weather, the child if the environment temperature is high or wear clothes too thick, there will be fear of heat sweating, is a normal physiological phenomenon, without special treatment. 2. Vitamin D deficiency: children afraid of heat sweating may be caused by a lack of vitamin D, children will also be accompanied by excessive sweating, baldness, irritability and crying, bone development deformities and other manifestations. 3. hyperthyroidism: children afraid of heat sweating may also be caused by hyperthyroidism. In addition to the fear of heat sweating, patients with hyperthyroidism will also be accompanied by panic, irritability, polyphagia, emaciation, as well as varying degrees of thyroid enlargement and eye protrusion. Children who are afraid of heat and sweat a lot, there may be other reasons, it is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.