Nosebleeds (epistaxis) happen when a small blood vessel inside the nose breaks and bleeds. The nose is lined with many tiny vessels near the surface, so even minor irritations or injuries can start bleeding. Common triggers include dry air, nose picking, blowing the nose too hard, colds or allergies, and minor nose trauma. Less common causes can involve medication effects (such as blood thinners or frequent decongestant spray use), infections, structural issues (like a deviated septum), or underlying health conditions that affect blood clotting. Key points about causes and risk factors

• Dry air and irritation: Dry indoor air, especially in winter or in arid environments, dries the nasal membranes and makes vessels more prone to bleeding.
• Mechanical irritation: Nose picking, aggressive blowing, or inserting objects into the nose can tear a vessel.
• Infections and inflammation: Colds, allergies, and sinusitis can inflame nasal tissues and vessels.
• Medications and health conditions: Anticoagulants (blood thinners), antiplatelet drugs, aspirin, or bleeding disorders can increase nosebleed risk; high blood pressure is often mentioned but is not a common direct cause of nosebleeds.
• Structural factors: A deviated septum or nasal polyps can predispose to localized bleeding.
• Less common causes: Cocaine use, chemical irritants, recent nasal or sinus surgery, or tumors, though these are far less typical.

What to do if you or someone else has a nosebleed

• Stay calm and sit up straight, leaning slightly forward to avoid swallowing blood.
• Pinch the soft part of the nose (just below the bridge) with your thumb and index finger for about 5–10 minutes continuously.
• Breathe through the mouth during the pinch, and avoid tilting the head back (to prevent swallowing blood).
• If bleeding lasts more than 20 minutes, or if it follows a facial injury, or if there are signs of heavy bleeding, fainting, or you suspect a serious underlying condition, seek medical care.

Prevention tips

• Keep nasal passages moist with saline sprays or humidifiers, especially in dry climates or heated indoor environments.
• Avoid nose picking and limit forceful nose blowing.
• Manage allergies or colds with appropriate treatments as advised by a clinician.
• Be cautious with medications that affect blood clotting as directed by a healthcare provider.

If you’d like, I can tailor this to your situation (age, medical history, current medications) and provide a quick step-by-step plan or a home-care checklist.