Four-month-old babies scratching their ears may be caused by physiological factors, mosquito bites, external ear canal eczema, otitis media and other factors. 1. Physiological factors: because the baby after birth for the outside world is more curious, there may be the phenomenon of scratching the ears, usually no other clinical manifestations, is a normal physiological phenomenon. 2. Mosquito bites: more indoor mosquitoes, the baby’s ear bites, may make the ear localized itching, which will lead to the baby scratching the ear to relieve the symptoms of itching, may also be accompanied by local redness, swelling and other symptoms. 3. Eczema of the external auditory canal: it may be related to environmental factors, external stimuli and other factors, which may cause pimples to appear in the external auditory canal, accompanied by obvious itching, and the baby will scratch the ear to relieve the itching, which may be accompanied by redness, swelling and vesiculation and other symptoms. 4. otitis media: usually associated with bacterial infection, the aggravation of the infection can lead to local itching and pus, resulting in ear discomfort, which will lead to frequent scratching of the baby’s ears, can be found in the ear secretion increase, acute attack, fever, fatigue and other symptoms. Four-month-old baby scratching ears, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.