Coughing and nose bleeding may be caused by upper respiratory tract infection, allergic rhinitis, nasopharyngeal carcinoma and other reasons. 1. Upper respiratory tract infection: after the virus invades the organism through the respiratory tract, it leads to acute inflammatory reaction of the mucous membrane in the nasal cavity, pharynx and other parts of the body, and the increase of capillary permeability, so it will lead to nose bleeding and coughing. 2. Allergic rhinitis: after contact with pollen, dust, dander, hair, seafood, willow floss and other allergens stimulation, the nasal mucosa acute allergic reaction, nasal mucosal edema, nasal itching and nose blowing increased, which can lead to local mucosal rupture and bleeding, secretion reflux stimulation of the pharyngeal mucosa or because of the allergic reaction of the pharynx; so it will be coughing and nose bleeding. Cough nose bleeding, there may be upper airway cough syndrome and other causes, it is recommended to consult a doctor to clarify the diagnosis.