Nasal polyps

Veterinary advice should be sought before applying any treatment or vaccine.

Nasal Polyps

Sinonasal Polyps, Inflammatory Polyps

Nasal polyps are soft, painless, noncancerous, inflammatory growths that can affect the horse's upper respiratory system. They occur most often unilaterally as singular or multiple masses in the nasal cavity of the horse. Onset of signs can be insidious and worsen over a prolonged period of time. Nasal polyps are thought to form due to a variety of possible mechanisms which include allergy, enzyme, mechanical obstruction, epithelial rupture, and abnormal transepithelial ion transport. If nasal polyps obstruct sinus drainage, subsequent infection can cause more stasis and swelling, which end up causing a self-perpetuating cycle.

There are several conditions that are associated with nasal polyps which include allergies, sinusitis, rhinitis, aspirin intolerance, asthma, cystic fibrosis, primary ciliary dyskinesia, immunodeficiency, and churg-strauss syndrome. The severity of nasal polyps identified during endoscopy are evaluated on a scale from 0-3.


Exercise intolerance
Malodorous nasal discharge
Increased respiratory noise
Enlarged lymph nodes
Facial swelling


  • History
  • Clinical signs
  • Physical exam
  • Endoscopy
  • Computed tomography (CT) } Magnetic resonance imaging (MRI)



Antihistamines and Decongestants - may provide some relief but are not a long term strategy
Surgery - Surgical removal of the polyps is a recommended treatment if other medical therapies are not successful.

Scientific Research

General Overviews

Age Range

Most commonly diagnosed in older horses.