Sudden bleeding from the nose may be related to dry rhinitis, leukemia, deviated nasal septum and other causes. 1. Dry rhinitis: this disease is often manifested as dry nasal mucosa, the surface of the turbinate is cracked and crusted, and there is often blowing the nose or involuntary bleeding phenomenon. 2. Leukemia: Leukemia can cause thrombocytopenia, which can affect the physiological hemostasis function, and sudden bleeding from the nose may occur. 3. Deviated septum: If you suffer from deviated septum, you may have persistent nasal congestion, nose bleeding and headache. Sudden bleeding from the nose may also be caused by tumors, etc. You should go to the regular hospital in time to clarify the cause, and if you need treatment, you should standardize the treatment under the guidance of the doctor, so as not to delay the condition and bring adverse effects to the body.