Nine-year-old boy old nosebleed may be related to nasal diseases, blood diseases, bad habits and other reasons. 1. Nasal diseases: such as chronic sinusitis, can be in the repeated stimulation of inflammation, capillary rupture can occur, resulting in children often nosebleed. 2. Blood diseases: such as leukemia, due to thrombocytopenia, can lead to coagulation dysfunction, causing the boy old nosebleed. 3. Bad habits: the nasal vestibule mucosa is rich in capillaries, if the boy has often digging nostrils and other bad habits, may make the nasal vestibule capillary rupture, may appear old nosebleed phenomenon. It is recommended that parents take their children to the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor to avoid delaying the condition.