Sudden nosebleeds can be caused by dry air, an underlying health condition, such as allergies, liver disease, kidney disease or a heart condition, such as hypertension or congestive heart failure. Additionally, a sudden nosebleed can be caused by blood-thinning medications and nonsteroidal anti-inflammatory drugs, explains Everyday Health.
Dry air is the most common cause of nosebleeds, as it can dry the lining of the nose, causing it to crack and bleed, states Healthline. Colds, allergies and frequent nose-blowing can also irritate the nasal lining and cause a nosebleed, reports Everyday Health.
A hypertensive crisis can cause a sudden increase in blood pressure that causes a nosebleed. Underlying health conditions, such as liver disease or kidney disease, can also cause the nose to bleed, as these diseases reduce the blood’s ability to clot. Additionally, medications like blood-thinners and nonsteroidal anti-inflammatory drugs can cause a nosebleed by altering the blood’s clotting ability, explains Everyday Health.