Nose bleeding for no reason may be caused by environmental factors and injuries, may also be the manifestation of certain diseases, such as atrophic rhinitis, dry syndrome, etc., should be timely consultation to identify the cause of the disease. 1. Environmental factors and injuries: dryness of the nasal mucosa due to dry weather, which in turn ruptures the capillaries and causes bleeding. Frequent picking of the nose can cause damage to the mucous membrane, which can lead to bleeding. 2. Pathologic factors: (1) atrophic rhinitis: it can be caused by systemic diseases, mainly manifested as nasal congestion, nasal dryness, nasal bleeding, loss of smell or loss of sense of smell, dizziness, headache and other symptoms, and in severe cases, there is a special putrid odor when exhaling. (2) Dry syndrome: generally manifested as a dry phenomenon throughout the body, including nasal dryness and discomfort, due to the attachment of scabs, which can cause nasal breathing, so that patients often use their hands to dig up the nose, peeling off the scabs, resulting in repeated small amount of bleeding, pain and so on. In addition to the above factors, it is not excluded that it is caused by other factors, such as tumors and so on. It is recommended that if you exclude physiological causes, you should consult a doctor in time to clarify the cause of the disease and give targeted treatment.