Two weeks old baby nosebleed may be dry nasal mucosa, allergic rhinitis, nasal vascular development deformity, coagulation function abnormality and so on. 1. dry nasal mucosa: excessive dryness may make the baby appear dry nasal mucosa, then the capillaries in the nasal mucosa are more prone to rupture, which may make the 2-week-old baby appear nosebleed symptoms. 2. allergic rhinitis: allergic rhinitis will make the capillaries in the nasal cavity have edema and congestion, and may also have the symptom of frequent sneezing, which may make the capillaries rupture, thus letting the 2-week-old baby nosebleed. 3. Nasal vascular malformations: Nasal vascular malformations or hemangiomas may make the blood vessels easy to rupture, which may cause 2-week-old babies to have nosebleeds. 4. Abnormal coagulation function: If the baby has abnormal coagulation function, such as babies with hemophilia, immune thrombocytopenic purpura, abnormal platelet count, abnormal coagulation factors, and other factors, it may also cause blood to keep flowing out, which will make the baby have nosebleeds. If 2-week-old babies often have symptoms of nosebleeds, they can first be given pressure on both sides of the nose to stop bleeding, such as nosebleeds can not be stopped or repeated nosebleeds, should be sent to the hospital immediately for treatment.