Most nosebleeds are not usually serious and can be stopped with home treatment. Most nosebleeds occur in the front of the nose (anterior epistaxis) and involve only one nostril. Some blood may drain down the back of the nose into the throat. Many things may make a nosebleed more likely.
Changes in the environment. For example:
Cold, dry climates; low humidity
Injury to the nose. For example:
Hitting or bumping the nose
Blowing or picking the nose
Piercing the nose
An object in the nose. This is more common in children, who may put things up their noses, but may be found in adults, especially after an automobile accident, when a piece of glass may have entered the nose.
A less common but more serious type of nosebleed starts in the back of the nose (posterior epistaxis) and often involves both nostrils. Large amounts of blood may run down the back of the throat. Posterior epistaxis occurs more often in older adults because of other health conditions they may have. Medical treatment will be needed to control the bleeding from posterior epistaxis.