Epistaxis is the presence of blood at the external nares. It is not a disease alone and there are many underlying conditions that cause this clinical sign. There are many causes of epistaxis, which fall into various categories. Below is a comprehensive list of all causes of epistaxis. | Epistaxis is the presence of blood at the external nares. It is not a disease alone and there are many underlying conditions that cause this clinical sign. There are many causes of epistaxis, which fall into various categories. Below is a comprehensive list of all causes of epistaxis. |