Reasons why children have unexplained nosebleeds in the middle of the night. Parents often feel panicked when children suddenly have nosebleeds at night and don\’t know how to deal with it. In order to better understand and deal with this situation, let\’s analyze the reasons why children have unexplained nosebleeds in the middle of the night from four aspects. 1. Physiological reasons: Children’s nasal mucosa is more fragile than adults and is more susceptible to irritation and nosebleeds. If a child has a sudden nosebleed, it may be caused by rubbing the nose, coughing, sneezing, etc. In addition, when sleeping at night, the environment is relatively dry, which can easily make the nasal mucosa dry and itchy.