A nosebleed, also caused epistaxis, can result from many causes. Up to 60 percent of people have experienced a nosebleed, notes the American Academy of Family Physicians. While usually not life threatening, the possibility of serious bleeding from the nose exists, according to MayoClinic.com. A nosebleed that is severe, lasts longer than 20 minutes, causes difficulty breathing or that is caused by an injury requires medical attention.
Trauma
Local trauma resulting from picking the nose, called epistaxis digitorum, or from blowing the nose is the most common cause of a nosebleed, explains Merck Manual Online Medical Library. They occur more frequently during colds and allergies for this reason. Injuries from accidents or fights can also cause the nose to bleed, and require medical attention.
The Environment
Low humidity can cause the nasal mucosa to become dry and irritated and cause nosebleeds, according to the National Institutes of Health website Medline Plus. Nosebleeds caused by low humidity happen more frequently in the winter when indoor air is heated. Dry climates, such as the desert, can also result in nosebleeds.
Foreign Bodies
A foreign object stuck in the nose can cause bleeding. This is more commonly found in children. Symptoms can include frequent bleeding and a foul smelling nasal discharge. Medical attention may be required to remove an object that is deeply inserted in the nasal cavity.
Medical Causes
Diseases that reduce the ability of blood to clot can cause nosebleeds. Hemophilia, hereditary hemorrhagic telangiectasia, idiopathic thrombocytopenic purpura, leukemia, nasal polyps and tumors, sarcoidosis and lupus are potential medical causes, according to MayoClinic.com.
Medications and Chemicals
Medications that thin the blood, such as heparin, coumadin, aspirin and ibuprofen can cause epistaxis. Chemical irritants, such as decongestant and corticosteroid nasal sprays and cigarette smoke, can cause bleeding if used frequently. Snorting cocaine and other drugs can cause bleeding and severe damage to the the tissue that separates the two sides of the nose, called the septum.
