Nosebleeds in children are mainly caused by nasal trauma, inflammation or systemic diseases. 1. Nasal trauma: when the nose is hit by the outside world, fall or picking the nose, it will cause the rupture of the blood vessels of the nasal mucosa and the symptom of bleeding; it is necessary to consult a doctor in time for the treatment of hemostasis and swelling in order to avoid a lot of bleeding and so on. 2. Inflammation: rhinitis, sinusitis, etc. can also cause damage to the nasal mucosa, resulting in bleeding, runny nose, fever or headache and other symptoms. 3. Systemic diseases: blood system diseases such as leukemia, hemophilia, etc. will lead to abnormal blood coagulation function, which makes the nasal mucosa susceptible to external stimuli and bleeding symptoms; in addition, the lack of vitamin C can lead to an increase in the brittleness of capillaries, which will also make the nose easy to bleed. Children with nosebleeds, there may be other reasons, 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.