Three and a half months of the baby sleep always shaking his head for many reasons, may be physiological factors, but also may be related to external factors, lack of micronutrients, eczema or other disease factors, parents need to carefully observe the baby with or without other manifestations or symptoms of discomfort, it is recommended to consult a medical professional, and then deal with it accordingly. Common causes and treatments I. Physiological factors: the baby is small, neurological function is in the developmental stage, before going to sleep or during light sleep, there may be shaking head rubbing, is a normal situation, generally do not need to deal with. Second, external factors: the environment temperature is high, the baby sweats more, causing scalp itching, or ear wax in the ear is not cleaned up, resulting in itching, the baby may be shaking his head, you can add or reduce the appropriate quilt, clothing. Third, disease factors: 1, lack of vitamin D, calcium: baby body lack of vitamin D, calcium, there will be crying and restlessness during sleep, shaking head, easy to wake up and other symptoms. Follow the doctor’s advice to take vitamin D supplements or calcium; 2, eczema: may be related to genetics, environment, immunity, often recurring episodes, such as eczema on the head, face, or external auditory canal, the baby can not be touched with the hand, so there is a shaking of the head phenomenon. It is recommended to consult a doctor for treatment, and need to use topical glycerite lotion or apply pimecrolimus cream and other creams for the treatment of eczema under the guidance of a doctor; 3. Other: if the baby suffers from ear canal eczema, otitis media and other conditions, such symptoms can also occur, it is recommended to consult a doctor in a timely manner, and according to the cause of the treatment.