An occasional nosebleed shouldn’t cause any problems, but you should see a provider if you have frequent nose bleeds or a bleed that doesn’t stop after 20 minutes. The nose contains many small blood vessels, so nose bleeds are rather common. In most cases, they are nothing to worry about. Some causes of nose bleeds include allergic reactions from rhinitis, blowing the nose too hard, overuse of nasal sprays, upper respiratory infections, or exposure to dry air. A nosebleed might also occur if you have a bone injury to your nose or sneeze repeatedly.