Anterior epistaxis typically originates from the Kiesselbach's plexus on the anterior part of the nasal septum and is usually visible on anterior rhinoscopy. It is the most common type of nosebleed and presents with bleeding from the front of the nose, often unilateral and less severe.
Posterior epistaxis arises from branches of the sphenopalatine artery located deeper in the nasal cavity, often not visible on anterior examination. It tends to cause bleeding from the back of the nose, may be bilateral, and is generally more severe, with blood potentially draining down the throat.
During clinical assessment, anterior epistaxis is identified by direct visualization of the bleeding site in the anterior nasal cavity, whereas posterior epistaxis is suspected if bleeding is profuse, not visible anteriorly, or if blood flows down the oropharynx rather than out of the nostrils.
Referral to secondary care is recommended for suspected posterior epistaxis due to higher risk of complications such as bradycardia, hypotension, hypoventilation, or aspiration.