1, acute febrile infectious diseases children often occur some rapid onset, high fever infectious diseases, especially the upper respiratory tract infection is more common. When high fever occurs, the blood vessels of the skin and mucous membranes throughout the body become congested and swollen, and the nasal mucosa also undergoes such pathological changes. The acute congestion and swelling of the nasal mucosa is more likely to cause rupture and bleeding because the nasal mucosa hail vessels are superficial, and once the fever is severe, coupled with the external force of blowing the nose, the blood vessels under the mucosa will rupture and bleed. 2, trauma nose is an organ exposed on the body surface, once trauma occurs, such as blows, bruises, nose naturally bear the brunt. Under the impact of severe trauma, the blood vessels under the mucous membrane will rupture and bleed. 3, nose digging strictly speaking, nose digging should also be included in the scope of trauma. Children often like to dig blindly with their fingers in the nasal cavity out of curiosity and difficulty, which is a bad habit that is not only unhygienic, but also easy to cause local mucosal bleeding in the nasal cavity. The general digging site is under the front of the nasal septum, and there are many blood vessels in this area, many tiny blood vessels are interwoven into a series of mesh, like a spider web, the blood vessels are superficial and very fine, the site is in the nasal cavity mouth, as long as the hand digging, you can dig through the blood vessels. More than 90% of children’s nasal bleeding is here. 4, nasal foreign body usually, the nasal cavity in addition to some secretion produced by the nasal snot, there is no object blocking the nasal cavity, so that breathing free and clear. But sometimes, children like to stuff some small objects in the nasal cavity, such as peanuts, melon seeds, fruit kernels, soybeans, plastic paper, small metal toys, etc., because of playfulness and fun. Once these objects are stuffed into the nose and become foreign bodies, the children themselves can not get out, and do not dare to voice, over time, they will be forgotten and stay in the nasal cavity. Some foreign objects swell and mold in the nasal cavity with water, causing nasal mucosa infection, erosion and bleeding, and sometimes under the bad stimulation of foreign objects, the nasal mucosa can also cause traumatic bleeding. 5, blood disorders in the human blood vessels to achieve neither bleeding, nor agglutination, all by some special factors in the blood. If under the action of some factors, some factors in the blood will undergo a series of changes, so that the blood vessels and blood in the occurrence of bleeding, it is not easy to agglutinate stop wish these diseases are leukemia and hemophilia and thrombocytopenic purpura, aplastic anemia, etc., collectively known as blood glass this is a direct cause of nosebleeds in children, and can cause repeated, massive bleeding. 6, rhinitis, paranasal sinusitis children are also prone to acute and chronic rhinitis and paranasal sinusitis. Once this inflammation occurs, the mucous membrane in the nasal cavity or paranasal sinus becomes congested and swollen, and from time to time there is mucopurulent nasal discharge, and under the stimulation of purulent nasal discharge, the blood vessels under the mucous membrane will also bleed.