causes of nosebleeds
Most commonly, trauma to the nose triggers a nosebleed. Trauma to the outside of the nose, such as a blow to the face, or trauma inside the nose, such as nose picking or repeated irritation from a cold, can cause a nosebleed. Less commonly, an underlying disease process, such as an inability of the blood to clot, may contribute to the bleeding.
Repeated nosebleeds may be a symptom of another disease such as high blood pressure, a bleeding disorder, or a tumor of the nose or sinuses. Blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin, may cause or worsen nosebleeds.
Nosebleeds are very common. Most nosebleeds occur because of minor irritations or colds. 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. Crusts can form that bleed when irritated. Nosebleeds occur more often in the winter, when cold viruses are common and indoor air tends to be drier.
Inability of the blood to clot is most often due to blood-thinning drugs such as warfarin (Coumadin) or aspirin. Liver disease can also interfere with blood clotting. Abnormal blood vessels or cancers in the nose are rare causes of nosebleeds.