Nosebleeds, also called epistaxis (ep-ih-STAK-sis), involve bleeding from the inside of your nose. Many people have occasional nosebleeds, particularly younger children and older adults.

Although nosebleeds may be scary, they're generally only a minor annoyance and aren't dangerous. Frequent nosebleeds are those that occur more than once a week.

The lining of your nose contains many tiny blood vessels that lie close to the surface and are easily irritated.

The two most common causes of nosebleeds are:

• Dry air — when your nasal membranes dry out, they're more susceptible to bleeding and infections
• Nose picking

Other causes of nosebleeds include:

• Acute sinusitis
• Allergies
• Aspirin use
• Bleeding disorders, such as hemophilia
• Blood thinners (anticoagulants), such as warfarin and heparin
• Chemical irritants, such as ammonia
• Chronic sinusitis
• Cocaine use
• Common cold
• Deviated septum
• Object in the nose
• Nasal sprays, such as those used to treat allergies, if used frequently
• Nonallergic rhinitis
• Trauma to the nose

Less common causes of nosebleeds include:

• Alcohol use
• Hereditary hemorrhagic telangiectasia
• Immune thrombocytopenia (ITP)
• Leukemia
• Nasal and paranasal tumors
• Nasal polyps
• Nasal surgery

In general, nosebleeds are not a symptom or result of high blood pressure.

Most nosebleeds aren't serious and will stop on their own or by following self-care steps.

Seek emergency medical care if nosebleeds:

• Follow an injury, such as a car accident
• Involve a greater than expected amount of blood
• Interfere with breathing
• Last longer than 30 minutes even with compression
• Occur in children younger than age 2

Don't drive yourself to an emergency room if you're losing a lot of blood. Call 911 or your local emergency number or have someone drive you.

Talk to your doctor if you're having frequent nosebleeds, even if you can stop them fairly easily. It's important to determine the cause of frequent nosebleeds.

Self-care steps for occasional nosebleeds include:

• Sit upright and lean forward. Remaining upright and sitting forward will help you avoid swallowing blood, which can irritate your stomach.
• Gently blow your nose to clear out any clotted blood. Spray a nasal decongestant in your nose.
• Pinch your nose. Use your thumb and index finger to pinch both nostrils shut, even if only one side is bleeding. Breathe through your mouth. Continue to pinch for 10 to 15 minutes by the clock. This maneuver puts pressure on the bleeding point on the nasal septum and often stops the flow of blood. If the bleeding is coming from higher up, the doctor may need to apply packing up into your nose if it doesn't stop on its own.
• Repeat. If the bleeding doesn't stop, repeat these steps for up to a total of 15 minutes.

After the bleeding has stopped, to keep it from starting again, don't pick or blow your nose and don't bend down for several hours. Keep your head higher than the level of your heart.

Tips to help prevent nosebleeds include:

• Keeping the lining of the nose moist. Especially during colder months when air is dry, apply a thin, light coating of petroleum jelly (Vaseline) or other ointment with a cotton swab three times a day. Saline nasal spray also can help moisten dry nasal membranes.
• Trimming your child's fingernails. Keeping fingernails short helps discourage nose picking.
• Using a humidifier. A humidifier may counteract the effects of dry air by adding moisture to the air.