nosebleed, nasal hemorrhage occurring as the result of local injury or disturbance. Most nosebleeds are not serious and occur when one of the small veins of the septum (the partition between the nostrils) ruptures. These will usually stop without treatment or when pressure is applied to the nose. A nosebleed may also occur in association with infections, heart failure, hypertension (high blood pressure), arteriosclerosis, scurvy, leukemia, hemophilia, and other disorders. Persistent nosebleeds should be brought to the attention of a physician, who can stop the bleeding with vasoconstrictors and topical anesthetics.