Sweaty head of toddlers may be caused by physiological factors such as overdressing and high temperature, or it may be caused by diseases such as vitamin D deficiency rickets and hyperhidrosis. 1. Physiological factors: if the toddler is overdressed or the temperature is high, the toddler’s body temperature will increase through sweating to dissipate heat, which will lead to excessive sweating on the head. 2. Vitamin D deficiency rickets: Vitamin D deficiency rickets is a malfunction of calcium and phosphorus metabolism caused by vitamin D deficiency, and children will have sweating, easy to frighten, pallor, and muscle weakness and other symptoms, which can lead to excessive sweating of the head of the child. 3. Hyperhidrosis: Hyperhidrosis refers to an abnormal increase in local or generalized skin sweating, young children suffering from hyperhidrosis, usually caused by hereditary factors, can be manifested as persistent paroxysmal hyperhidrosis, mostly confined hyperhidrosis, such as the head and other places. There may be other causes of excessive sweating in the head of young children, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.