In patients with deviated septum or septal spurs in the anterior portion of the nose, trauma occurs easily, either from the drying effects of poorly humidified air or secondary to probing in or bumps on the nose. Nose picking, nose rubbing, or forceful nose blowing may also trigger bleeding when the nasal mucosa is inflamed and fragile from a viral, bacterial, or allergic cause.

Ulcerations, which tend to form over septal deviations and spurs, bleed easily. Repeated mucosal exposure to cocaine leads to anoxic tissue necrosis from drug-induced intense vasospasm; perforation may result from cocaine use and cause chronic crusting and bleeding. Collagen diseases such as lupus are occasionally responsible for ulceration. The prolonged use of the widely prescribed topical nasal steroid sprays may lead to anterior septal mucosal atrophy and may be followed by frank ulcer formation or, in rare cases, septal perforation.

Bleeding diatheses sometimes present as epistaxis (see Chapter 81). Nosebleeds are the most common initial presentation of hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) and its most frequent bleeding complication. Characteristic features include telangiectasias on the nasal mucosa, lips, and tongue; a positive family history; and onset of repeated bleeding episodes by the third or fourth decade. Adolescent boys with a nasopharyngeal angiofibroma experience repeated bouts of brisk posterior epistaxis. Sinus x-rays or computed tomographic scan imaging with contrast demonstrate a nasopharyngeal mass. Patients taking warfarin, high-dose aspirin, and other antiplatelet agents may present with complex epistaxis, sometimes with multiple sites of bleeding, unresponsive to standard conservative measures.

Wegener granulomatosis, midline granuloma, and nasal malignancy share a presentation of epistaxis, unremitting sinus infection, and opacified sinuses on three-dimensional imaging.

Posterior epistaxis, most commonly due to bleeding from the sphenopalatine plexus deep in the nose, is commonly attributed to hypertension, but epidemiologic studies show that few hypertensive individuals experience nosebleeds.

Active anterior epistaxis usually presents as unilateral, continuous, moderate bleeding from the anterior septum called the Kiesselbach plexus. Recurrent episodes of bleeding, lasting from a few minutes to half hour over the preceding few days and controlled by pinching the anterior nose, are characteristic. Most adult cases and almost all spontaneous nasal hemorrhage in children occur on the anterior aspect of the nasal septum. Most are venous, but an arterial source becomes more common with advancing age because of mucosal and vascular atrophy. Anterior epistaxis remains the most common site for patients taking antiplatelet agents. Anterior nosebleeds account for roughly 90% of all epistaxis episodes.

Posterior epistaxis is associated with intermittent, very brisk arterial bleeding, with blood flowing posteriorly into the pharynx unless the patient is leaning forward. When the patient is leaning forward, the blood may run from one or both sides of the nose. Spontaneous posterior hemorrhage is more common in the older age groups and after severe facial trauma with multiple facial fractures. The vessel rupture is usually just superior or inferior to the posterior tip of the inferior turbinate on the lateral nasal wall from the sphenopalatine artery.