Nosebleeds in eight-year-old children may be caused by nose picking, nasal dryness, rhinitis, blood system disorders and so on. 1. Nose picking: If children have the habit of picking their nose, it will easily lead to rupture of the nasal mucosa, thus causing nosebleeds. 2. Nasal dryness: often related to the climate, may be due to the dry climate leads to dry nasal mucosa, capillary fragility increases, it is easy to rupture bleeding. 3. Rhinitis: when suffering from rhinitis, due to inflammation stimulation will lead to nasal mucosa congestion and edema, capillary permeability increases, easy to cause nosebleeds. 4. Blood system diseases: such as thrombocytopenia, coagulation disorders, etc., may lead to blood vessel rupture, causing nosebleeds. Nosebleeds in eight-year-old children 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.