Causes of Nose Bleeding

Nasal allergies.
Blowing your nose too hard or trying to remove something from inside the nose.
Nasal exposure to chemicals.
Frequent sneezing or having an upper respiratory infection.
Use of nasal spray or a blood-thinning drug, such as aspirin.
Inhaling air that is extremely dry or cold.
Having recent surgery on the nose or elsewhere on the face.
Breaking the nose or a similar injury.