Why Do Nosebleeds Happen? Common Causes Explained
Nosebleeds are one of the most common minor medical events people experience. About 60% of people will have at least one nosebleed in their lifetime, and they're especially frequent in children and young adults. But why do they happen?
The inside of your nose is lined with thin, delicate blood vessels very close to the surface. It doesn't take much to rupture one. Most nosebleeds originate from the septum — the wall between your two nostrils — in an area called Kiesselbach's plexus, where several blood vessels converge.
The Most Common Causes
Dry Air
The number one cause. Heated indoor air during winter, arid climates, and air-conditioned environments all dry out the nasal membranes. When the lining of your nose dries out, it cracks and bleeds. This is why nosebleeds spike in winter months and on long flights where cabin humidity drops below 20%.
Nose Picking and Rubbing
The most common cause in children. Fingernails can easily scratch the delicate blood vessels inside the nose. Frequent nose blowing during a cold or allergies can have the same effect.
Sports and Physical Contact
A ball to the face, an elbow during a game, or even heading a soccer ball can trigger a nosebleed. Contact sports like basketball, football, wrestling, and martial arts see nosebleeds regularly. Even non-contact activities like running or cycling at high intensity can occasionally cause them due to increased blood pressure.
Allergies and Sinus Issues
Allergic rhinitis causes inflammation inside the nose, making blood vessels more fragile. Antihistamines and nasal sprays — the treatments for allergies — can also dry out the nasal lining and contribute to nosebleeds.
Altitude Changes
The air gets thinner and drier at higher elevations. Skiers, hikers, and people flying frequently are all more prone to nosebleeds. The combination of cold, dry air and lower atmospheric pressure makes nasal blood vessels more vulnerable.
Medications
Blood thinners like aspirin, ibuprofen, and prescription anticoagulants reduce the blood's ability to clot, making nosebleeds more likely and harder to stop. Nasal steroid sprays, when used long-term, can also thin the nasal lining.
When Should You Be Concerned?
Most nosebleeds are anterior (from the front of the nose) and harmless. They stop on their own or with simple pressure within 10-15 minutes.
Posterior nosebleeds — originating deeper in the nose — are less common but more serious. They tend to produce heavier bleeding, and blood may flow down the back of the throat even when sitting upright. These are more common in older adults and may require medical attention.
See a doctor if nosebleeds happen more than once a week, last longer than 20 minutes despite proper technique, follow a head injury, or are accompanied by other unusual bleeding or bruising.
Prevention
Keep the air in your home humidified during dry months. Apply a thin layer of petroleum jelly or saline gel to the inside of your nostrils before bed if you're prone to nosebleeds. Stay hydrated. And if you play sports or live at altitude, carry a nosebleed kit so you're ready when one happens.
Be prepared for nosebleeds wherever they happen.
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