Most frequent nosebleeds in small children are due to damage to the nasal mucosa, most often due to rhinitis. A few may be due to diseases of the blood system, such as aplastic anemia or leukemia. In allergic rhinitis in children, after contact with allergens, the nasal mucosa is always in a state of congestion and edema accompanied by itching. When itching, children are prone to scratching, which further aggravates the damage to the nasal mucosa, thus causing nosebleeds. If there are blood system diseases, such as aplastic anemia or leukemia, bone marrow anomalous hematopoietic syndrome can cause nosebleeds, need to go to the hospital in time to improve the blood routine, bone marrow aspiration biopsy, coagulation function, immunohistochemistry and other related tests to clarify the diagnosis, and comply with the doctor’s instructions for targeted treatment. Children often nosebleeds, it is recommended to consult the ENT clinic in a timely manner, under the guidance of the doctor to be targeted treatment.