There are several reasons why children have nosebleeds when they get excited: 1, caused by the increased brittleness of the nasal mucosa blood vessels, mainly due to dry room air and low humidity, which can lead to excessive dryness of the nasal cavity and can increase the brittleness of the nasal blood vessels. 2, colds and infections can lead to bacterial infection of the nasal mucosa, which can damage the nasal mucosa and lead to bleeding. 3, lack of vitamin C in children can also lead to increased brittleness of the nasal mucosa blood vessels. 4.Nosebleeds when children are excited may also be due to blood system diseases, including thrombocytopenia, coagulation dysfunction and other diseases that can lead to nosebleeds when children are excited, so they should go to the hospital for blood system tests for a clear diagnosis and symptomatic treatment.