Nosebleeds in children do not necessarily mean leukemia. Leukemia is the most common malignant disease of the blood system, especially in pediatric patients, who account for more than 90% of all malignant diseases. The so-called leukemia is due to the massive proliferation of leukemia cells in the bone marrow, the normal hematopoietic function is destroyed, and the patient develops a series of symptoms such as anemia, infection, bleeding, organ infiltration, etc., in which nosebleeds are likely to occur. However, in addition to nosebleeds, patients with leukemia often have fever, along with a series of symptoms such as anemia. If a child has a simple nosebleed, no fever, and no symptoms of anemia, it is likely to be caused by rich capillaries in the nasal vestibule, thin local mucosa or dry local nasal mucosa.