What causes a sudden nosebleed?

The front of the nose contains many small vessels close to the surface. Dry air, nose picking, forceful blowing, allergies, a cold, or sinus irritation can disturb them. Nosebleeds can occur during allergic rhinitis or a common cold; these conditions do not by themselves prove the cause of an individual episode. High blood pressure may make bleeding harder to control, while blood-thinning medicines can increase bleeding. Most episodes are from the front of the nose and stop with simple pressure.

Sit upright and lean slightly forward so blood does not run into your throat. Pinch the soft part of the nose firmly for ten to fifteen minutes without checking repeatedly. Breathe through your mouth. Do not tilt your head back, lie flat, blow your nose, or pick inside it while bleeding continues. Afterward, avoid heavy exertion and hot drinks for a short period, and keep the nasal lining moist with a suitable saline product if dryness is a recurring trigger.

Seek urgent medical help if bleeding is heavy, follows a significant injury, causes faintness or breathing difficulty, or continues despite sustained pressure. Arrange medical advice for repeated episodes, bleeding from other sites, easy bruising, or use of anticoagulant medicine. A clinician may check the nose, blood pressure, medicines, and possible irritation or infection.

Ask whether a medicine, nasal spray, allergy, or dryness may be contributing; whether your blood pressure needs checking; and how to prevent another episode safely.