Nosebleeds at night can be caused by nasal damage, dry air, allergies and other factors. 1. Nasal injury: when children pick their noses or rub their noses at night, it may lead to damage to the nasal mucosa and rupture of local capillaries, resulting in nosebleeds. 2. Dry air: dry indoor air at night can lead to an increase in the fragility of the nasal mucosa, which in turn causes nosebleeds. 3. Allergy: when sleeping at night, small children are allergic to mites and other allergens present on the bed sheets and bedding, it can aggravate nasal itching and increase the action of kneading the nose, which is easy to damage the nasal mucosa and nosebleed. Children with nosebleeds at night, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.