what causes a nose bleed

Most nosebleeds happen because the tiny blood vessels inside the nose get dry, irritated, or injured and then break and bleed.

Main everyday causes

• Dry air (winter heating, air conditioning, low humidity) dries the lining of your nose so it cracks and bleeds more easily.

• Colds, flu, and sinus infections inflame the nasal lining and make it more fragile.

• Allergies (and allergy sprays) can both irritate the nose and lead to frequent rubbing or blowing.

• Nose picking, rubbing, or scratching the inside of the nose directly injures small blood vessels, especially in children.

• Blowing your nose hard (especially when congested) can pop delicate vessels in the front of the nose.

• Minor trauma, like getting hit in the face with a ball or bumping your nose, can trigger a bleed.

Health and medication causes

Sometimes nosebleeds are easier to get because of what’s happening in the rest of the body.

• Blood-thinning medicines (like warfarin, heparin, or aspirin) make any small bleed last longer and seem heavier.

• Blood clotting or bleeding disorders (for example hemophilia, immune thrombocytopenia) mean blood vessels don’t seal well once they’re damaged.

• Heavy alcohol use can affect platelets and blood vessels, making bleeding more likely.

• Certain inherited conditions, like hereditary hemorrhagic telangiectasia, cause fragile abnormal blood vessels in the nose that bleed repeatedly.

• Serious illnesses such as leukemia can sometimes show up first as frequent or hard‑to‑stop nosebleeds, usually with other symptoms like bruising or fatigue.

Local nose problems

Issues inside the nose itself can also be behind recurrent nosebleeds.

• Deviated septum (the wall between nostrils is crooked) changes airflow and dries one side more, making it crack and bleed.

• Nasal polyps or other growths/tumors can disturb normal tissue and vessels so they bleed more easily.

• Chronic sinusitis keeps the lining swollen and fragile over time.

• Foreign objects in the nose (common in kids) can injure tissue and vessels.

Lifestyle and environmental triggers

• Cigarette smoke or chemical irritants (like ammonia or other strong fumes) damage the nasal lining and its blood vessels.

• Snorting drugs such as cocaine is very irritating and can cause repeated nosebleeds and long‑term damage inside the nose.

• Oxygen delivered through nasal prongs, especially without added humidity, can dry and irritate the lining.

When a nosebleed is more serious

Most nosebleeds are harmless and stop on their own, but some warning signs mean you should get medical help quickly.

• Bleeding that doesn’t stop after 15–20 minutes of firm pressure on the soft part of the nose.
• Very frequent nosebleeds (for example, several times a week) without a clear cause.
• Nosebleeds plus easy bruising, bleeding gums, or extreme tiredness.
• Nosebleeds after a significant head injury, or along with confusion or severe headache.
• Nosebleeds in someone on blood thinners that seem heavier than usual.

TL;DR: The most common causes of a nosebleed are dry air, colds or allergies, nose picking or hard blowing, and minor injuries; medicines, blood disorders, and structural nose problems are less common but important causes, especially when nosebleeds are frequent or hard to stop.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.