The causes of sudden nosebleeds in patients can be local causes of the nose itself, or perhaps systemic causes, as follows: 1. Local causes: Local causes include traumatic bleeding, such as regular nose picking, nose blowing, or nasal feeding to the patient, and traumatic bleeding, such as having nose surgery. The other is inflammation of the nose, such as acute rhinitis, acute sinusitis, and non-specific infectious inflammation caused by non-specific chemical irritation. Some people have deviated nasal septum, and nasal perforation may also bleed, in addition to sinus tumors may also bleed. 2, systemic diseases: systemic diseases, including blood diseases, such as leukemia, aplastic anemia, may be nasal bleeding. Some people have hypertension, arteriosclerosis, increased venous pressure, etc., and cause bleeding. In addition, patients with emphysema and pulmonary heart disease may also have nosebleeds. There are also vitamin deficiencies, such as vitamin E and vitamin K deficiencies, and some poisoning can cause nosebleeds. The presence of sepsis and uremia, these factors can also cause nosebleeds.