17-year-old teenager often nosebleed, may be related to the dry environment, bad nose picking habits, may also be due to the presence of rhinitis, nasopharyngeal fibroangioma, blood diseases and other causes. 1. Environmental dryness: environmental dryness can lead to dry nasal mucosa, capillary fragility increases, easy to occur nosebleeds. 2. Bad nose picking habits: the existence of bad nose picking habits can easily lead to nasal mucous membrane damage, and frequent nosebleeds will occur. 3. Rhinitis: acute rhinitis, dry rhinitis, atrophic rhinitis and other non-specific inflammation of the nose and sinuses, as a common cause of nosebleed. 4. Nasopharyngeal fibrous hemangioma: patients of this age should be alert to the possibility of nasopharyngeal fibrous hemangioma if they have symptoms of recurrent nosebleeds, and need to undergo nasal endoscopy and imaging to understand the condition. 5. blood disease: 17-year-old teenager if there is hemophilia, leukemia and other blood diseases, resulting in coagulation dysfunction, thrombocytopenia, there may be frequent nosebleed symptoms, may also be accompanied by mental lethargy, weakness and other manifestations. Seventeen-year-old teenager often nosebleed, there may be a deviated nasal septum, nasal septum capillary hemangioma, etc., should be as early as possible to seek medical treatment, through the improvement of relevant examination, diagnosis and diagnosis, give targeted treatment.