The common causes of children’s middle-of-the-night nosebleeds with blood clots are nasal mucous membrane ulceration, blood diseases and so on. 1. Nasal mucous membrane rupture: it can be seen in children with dry nasal cavity, cold, rhinitis, sinusitis, often with nose discomfort, and nose picking, nose blowing and other bad habits, especially at night, repeated nose picking will have nosebleeds, if not found in time, there can be the formation of blood clots. 2. Blood diseases: if you suffer from aplastic anemia and other blood system diseases, there are coagulation disorders or thrombocytopenia and other manifestations during the examination, a little bit of intranasal mucous membrane rupture, easy to have a nosebleed, it is not easy to find out in the middle of the night, and the blood in the nose will be accumulated to form a blood clot. Therefore, it is recommended to consult a regular hospital in time for a clear diagnosis and treatment of nosebleed.