Sweating in the head when the baby falls asleep may be caused by high metabolism, vitamin D deficiency, hyperthyroidism and tuberculosis. 1. vigorous metabolism: the baby’s metabolism is more vigorous than that of adults, so there will be the symptom that the baby fell asleep and sweated, which is generally a normal physiological phenomenon, and if there are no other symptoms, there is no need for special treatment. 2. lack of vitamin D: the baby fell asleep head sweat may be caused by the lack of vitamin D. If the baby lacks vitamin D, the baby will be able to get rid of it. If the baby lacks vitamin D, it will affect the absorption and utilization of calcium, phosphorus and other substances, manifested as sleep disturbance, easy to startle, excessive sweating, occipital baldness and so on. 3. hyperthyroidism: the baby fell asleep head sweat may be hyperthyroidism caused. The clinical symptoms of hyperthyroidism are palpitations, sweating, increased eating and pooping, and weight loss. 4. tuberculosis: the baby fell asleep head sweat may be caused by tuberculosis, the baby in addition to fall asleep head sweat, but also can be accompanied by afternoon low fever, fatigue, cough, hemoptysis and emaciation and other symptoms. The baby fell asleep head sweat, exclude physiological reasons, parents are advised to take the baby to the hospital in a timely manner, to avoid delaying the adverse consequences of the condition.