Why is the nose prone to bleeding?
The nose has many blood vessels in it to help warm and humidify the air you breathe. These vessels lie close to the surface, making them easy to injure.

Are nosebleeds serious?
A few nosebleeds stem from large vessels in the back of the nose. These nosebleeds can be dangerous. They may occur after an injury. This type of nosebleed is more common in the elderly and is often due to high blood pressure, atherosclerosis, daily aspirin use or bleeding disorders. Usually, the older the patient, the more serious the nosebleed.

You'll need to get medical attention if a nosebleed goes on for more than 20 minutes or if it occurs after an injury (such as a fall or a punch in the face), especially if you think you may have a broken nose. A nosebleed after a fall or car accident could be a sign of internal bleeding. Frequent nosebleeds may mean you have a more serious problem. For example, nosebleeds and bruising can be early signs of leukemia. Nosebleeds can also be a sign of a blood clotting or blood vessel disorder, or a nasal tumor (both cancerous and non-cancerous).

What causes nosebleeds?
The most common causes are dryness (often caused by indoor heat in the winter) and nose picking. These 2 things work together -- nose picking occurs more often when mucus in the nose is dry and crusty. ther, less common, causes include injuries, colds, allergies or cocaine use. Children may stick small objects up the nose. Older people may have atherosclerosis (which is the hardening of the arteries), infections, high blood pressure and blood clotting disorders, or they may be taking drugs that interfere with blood clotting, such as aspirin. A rare cause of frequent nosebleeds is a disorder called hereditary hemorrhagic telangiectasia (HHT). Sometimes, the cause of nosebleeds can't be determined.