An unstoppable nosebleed is not necessarily a precursor to leukemia. Causes of unstoppable nosebleeds include rhinitis, nasopharyngeal fibroangioma, and acute leukemia. Therefore, the nosebleed can be seen in leukemia patients, but not necessarily caused by leukemia. 1. Rhinitis: dry climate in autumn and winter causes dryness in the nose, decrease of secretion, formation of crusts on the surface of nasal mucosa, and bleeding due to damage of nasal mucosa caused by picking the nose with hands. 2. Nasopharyngeal fibrous hemangioma: the tumor is mostly fibrous tissue with abundant blood vessels and thin tube wall, which leads to larger bleeding after injury. 3. Acute leukemia: a large number of leukemia cells stagnation in blood vessels, platelet reduction, coupled with infection and other factors, it is easy to trigger bleeding symptoms. There may also be other reasons why the nosebleed won’t stop, such as nasal hemangioma. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment under the guidance of physicians.