Causes of pediatric rhinorrhea can be divided into rhinorrhea triggered by local factors and rhinorrhea caused by systemic factors. Local factors Common local causes in children are: 1. Dry rhinitis: It is the most common cause in children, usually due to dry nasal mucosa and increased vascular fragility, which triggers bleeding during defecation, sneezing and sleep, mostly caused by improper diet, such as not eating vegetables and drinking little water, accounting for more than 90% in clinical practice. 2, nasal foreign body or nose digging: 2 to 5 years old children like to dig their nose with their hands, or will be a variety of foreign objects into the nasal cavity, also often cause nasal bleeding, this case bleeding is less, but also a very common clinical phenomenon. 3, nasal trauma: is also one of the common causes of children, because children are more active, easier to have accidents than adults, the nose is also a more vulnerable part of the face, once injured will trigger nasal bleeding, and even more serious, bleeding volume. In addition, medical trauma, such as nasal endoscopic surgery, due to the small field of view of children, if improperly operated, easy to cause fractures of the sieve bone or pterygoid bone, triggering bleeding, hematoma and other situations. 4, acute and chronic inflammation of the nose: in general, children rhinitis sinusitis is much lighter than adults, the course of the disease is short, refractory rhinitis is rare, so the rhinorrhea caused by rhinitis alone is rare, the degree is also relatively light. 5, nasal tumors: during childhood, malignant tumors of the nasal cavity and sinuses and their rare, but nasal bleeding is often its first symptom. Among benign tumors, nasopharyngeal fibrovascular tumor is the most common cause of nasal bleeding, which is mostly seen in male adolescents around 8-20 years old, with heavy bleeding, repeatedly delayed, and eventually requiring surgical removal treatment. Nasal hemangioma can also cause nasal bleeding to varying degrees and often requires surgical treatment. Systemic factors Systemic factors of nasal bleeding in children are: 1. Hematological diseases: one of the common systemic factors causing nasal bleeding in children. Such as hemophilia, leukemia, thrombocytopenic purpura, aplastic anemia, etc. Childhood is a good stage for blood diseases, and nosebleeds are often their first symptom, so for patients with recurrent nosebleeds, blood screening, such as routine blood tests, should be performed to avoid missing the diagnosis. 2.Acute febrile diseases: including viral infection of upper respiratory tract infection, hemorrhagic fever, measles, etc., mainly due to high fever causing vascular nerve dysfunction and capillary rupture causing bleeding. 3, nutritional disorders or vitamin deficiency: such as vitamin C, K, P deficiency, vitamin C is closely related to vascular permeability; vitamin K is related to thrombospondin formation, and deficiency will cause rhinorrhea. In children, long-term partial eating is the main cause of nutritional disorders and micronutrient deficiencies. 4, systemic chronic diseases: such as hypertension, liver and kidney dysfunction can affect the coagulation function, but it is less common in children. 5, hereditary diseases: mostly seen in children, such as hereditary capillary dilation, Osler’s disease, as autosomal inherited diseases. The above causes can occur individually, and in complex cases there are multiple factors that must be carefully examined and analyzed for thorough consideration. Parents can contact me by phone if they have any questions.