One year old baby sweat hair wet can be seen in physiological phenomena, pathological conditions (such as vitamin D deficiency, febrile diseases or tuberculosis, etc.), the specific need to analyze and judge according to the baby’s situation. 1. physiological phenomenon: for the age of the baby in the feeding, activity or crying after the above performance, or part of the baby’s basic metabolism and sebaceous glands function exuberant, can appear sweaty hair wet phenomenon, usually normal growth and development, no other abnormal symptoms, is a normal physiological phenomenon. 2. Pathologic conditions: (1) Nutritional vitamin D deficiency rickets: in the early stage of the disease, there may be increased nerve excitability, such as the performance of excessive sweating, which may be accompanied by easy to annoy, etc., need to supplement vitamin D, more sunshine. (2) febrile diseases: such as infantile acute rash, in the disease state, the baby fever, the above performance can occur, through sweating to increase heat dissipation, body temperature gradually decline. (3) Tuberculosis: mostly caused by tuberculosis bacillus, the baby may have low fever, night sweats, mostly obvious at night, often with a history of contact with tuberculosis, perfect tuberculin test and chest X-ray can help diagnosis. It is recommended to consult a specialist physician to evaluate and determine the cause if necessary.