Children’s mouth blisters are usually related to the lack of trace elements, allergies, viral and bacterial infections. 1. Lack of trace elements: If the diet is too monotonous, drinking less water leads to the body lack of trace elements may cause mouth ulcers, usually manifested as ulcers blisters and other symptoms. 2. Allergies: children’s mouth blisters may also be eating foods that cause allergies, such as mango, seafood and so on. 3. Viral and bacterial infections: If a child is infected with viruses and bacteria that cause oral diseases, such as thrush, it usually manifests itself in the form of mouth blisters. There may be other reasons for children’s mouth blisters, it is recommended to go to the hospital in a timely manner, under the guidance of the doctor to determine the cause of the disease, if necessary, with the doctor’s treatment.