There are more causes of nosebleeds with high fever, usually related to rhinitis, leukemia, nasopharyngeal cancer and so on. The specific situation needs to be combined with other conditions and other symptoms to make a comprehensive judgment. 1. Rhinitis: If you suffer from acute rhinitis, due to the invasion of a large number of viruses as well as bacteria in a short period of time, it causes the body to have the symptom of immune fever. And if the mucous membrane of the nasal cavity is swollen drastically, it is possible to have nosebleeds. 2. Leukemia: Generally, if you suffer from some blood system diseases, such as leukemia, fever and nosebleed may occur in this case. 3. Nasopharyngeal cancer: if you suffer from malignant or advanced nasopharyngeal cancer, fever and nosebleed will occur after the cancer spreads in a large area of the body. When high fever and nosebleed occur, it is recommended to seek medical treatment in time and target treatment according to the condition.