A nosebleed is bleeding from tissues inside the nose (nasal mucus membranes) caused by a broken blood vessel. The medical word for nosebleed is epistaxis. Most nosebleeds in children occur in the front (anterior) part of the nose close to the nostrils. This part of the nose has many tiny blood vessels. These can be damaged easily. These nosebleeds are usually not serious.
Nosebleeds in the back part of the nose, near the throat (posterior) are less common in children than nosebleeds in the front. They can be more serious and cause a lot of blood loss.
A nosebleed can look scary, but is usually not a serious problem. Nosebleeds are common in children. They happen more often in dry climates. They also happen more during the winter. That's when dry heat in homes and buildings can cause drying, cracking, and crusting inside the nose. Many children outgrow nosebleeds during their teen years.