Nosebleeds in one-week-old babies may be caused by nasal dryness, or they may be caused by dry rhinitis, leukemia, and other diseases such as nasal trauma. 1. Nasal dryness: if the one-week-old baby is in a dry air environment for a long time, it will make the nasal cavity dry. If the patient’s nasal dryness leads to rupture of the nasal mucosa or nasal capillaries, the performance of nosebleed may occur. 2. Dry rhinitis: the etiology of dry rhinitis is not clear, and it is considered to be related to vitamin deficiency, anemia and other factors. Patients will appear nosebleed, nasal congestion, nasal secretion reduction and other symptoms. If the one-week-old baby appears dry rhinitis, there may be symptoms of nosebleed. 3. Leukemia: the cause of leukemia is still unclear, and it is considered to be related to heredity, gene mutation and other reasons. Patients will have anemia, bleeding, enlarged lymph nodes, splenomegaly and other symptoms. Therefore, one-week-old babies with leukemia will manifest as nosebleeds. 4. Other: one-week-old baby appearing nosebleed may also be nasal trauma, nasal tumor, nasal septum deviation, idiopathic thrombocytopenic purpura, allergic rhinitis and other diseases. It is recommended that one-week-old lesions appear nosebleeds, parents need to take their children to the doctor in a timely manner, if it is caused by nasal dryness, do not need treatment. If it is caused by disease, you can choose the appropriate measures under the guidance of the doctor to treat.