- Horse:
- Nasal aspergillosis
- Ethmoidal haematoma = 'Haemorrhagic nasal polyp', 'Progressive haematoma' - arise from the ethmoid region and can extend to fill the nasal cavity. They can be difficult to control as they can recur after surgery.
- Histology - multiple areas of acute to chronic haemorrhage within a fibrous tissue stroma.
- Exercise-induced pulmonary haemorrhage
- Rupture of rectus capitus - profuse haemorrhage
- Mycotic infection of guttural pouches
- Nasolacrimal haemorrhage
- Nasal/pharyngeal trauma/foreign body
- Sinus neoplasia
- Sinus cyst
- Sinusitis
- Lower airway disease
- Pulmonary neoplasia
- Cardiac
- Mitral insufficiency
- Atrial fibrillation
- Skeletal
- Head trauma
- Rarely hypertension or vascular aneurysms