The main causes of mouth blisters in children usually include thrush, mouth ulcers and traumatic blood blisters. 1. Thrush is usually caused by Candida infections, which may lead to decreased immunity and thus decreased drug resistance to blistering in the mouth. 2. Mouth ulcers are usually caused by poor diet or vitamin deficiencies, which may manifest as white herpes-like symptoms. 3. Traumatic blood blisters are usually blood blisters on the oral mucosa caused by eating rough food or stabbing with hard objects. Children’s mouth blisters may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.