Tiny and fragile blood vessels lining the nose are easily damaged, which causes nosebleeds. The U.S. National Library of Medicine and National Institutes of Health explain that nosebleeds are very common and rarely indicate life-threatening conditions. Occasional nosebleeds may suggest a more serious medical condition, requiring a physician's consultation for further diagnosis.
Allergies
According to the Mayo Clinic, allergies may cause nosebleeds, but this is not a common condition. The nose contains many small blood vessels that bleed easily. Air moving through the nose can dry and irritate the membranes lining the inside of the nose, forming crusts. These crusts bleed when irritated by rubbing, picking, or blowing the nose, state the U.S. National Library of Medicine and National Institutes of Health. The bleeding typically lasts for a few minutes and depends on the allergy intolerance of the individual. Allergies may also cause nasal drying, which is another reason for nose bleeds.
Deviated Septum
A deviated septum is the displacement of a nasal wall to one side. Dryness in the surface area of the nasal septum also increases the risk for nose bleeds. The American Academy of Otolaryngology indicates a severe displacement not only reduces airflow, but may result in persistent nosebleeds, requiring medical attention.
Hemophilia
Hemophilia is a disorder of the blood-clotting system, leading to persistent bleeding when a person is cut or wounded. Nosebleeds from rubbing or irritating the sensitive nasal area may occur with this condition.
Hypertensive Crisis
According to the American Heart Association, a hypertensive crisis, defined as a blood pressure reading of 180/110 mm Hg or more, may lead to nosebleeds. Blood pressure leading to a hypertensive crisis and nosebleed is cause for immediate medical attention. Blood pressure at normal range or slightly above does not commonly cause nosebleeds.
