What Equine Nasal Discharge Tells Us

Causes of snotty noses can range from benign to catastrophic


It starts with a drip: a bit of clear nasal discharge apparent as you wipe one of your horse’s nostrils while tacking up. It’s chilly out and, quite honestly, your own nose is running a bit, so you think it’s probably nothing.


Most likely, it’s not anything to be concerned about. But even with something as seemingly simple as a horse with a snotty nose, it’s important to pay attention and know how problematic the discharge is, the possible causes behind it, and when to call your veterinarian. Nasal drainage can be due to something as basic as a dusty arena to a life-threatening emergency. Many other causes fall between the two extremes.


The mucous membranes lining your horse’s nasal passages are sensitive, just like yours. Anything, infectious or not, that aggravates them or causes inflammation can lead to production of additional mucus or fluid and the telltale runny nose.


In this article we’ll look at six snotty scenarios and explore the possible causes. Some are fairly benign, while others require calling a veterinarian to resolve the issue and protect nearby horses. Still, some can be life-threatening.

Describing the Discharge


When faced with a snotty nose, it’s important for a horse owner or caregiver to make certain observations before calling the veterinarian. First, it’s important to characterize the discharge based on:

  • Color;
  • Consistency (viscosity, watery vs. thick vs. foamy, etc.);
  • Amount;
  • Whether it is bilateral or unilateral;
  • Whether it has an odor and what type; and
  • Whether blood is present.

Understanding common terms a veterinarian might use to describe discharge can help owners and caretakers communicate more effectively, as well:

  • Serous: watery discharge
  • Mucoid: opaque white discharge
  • Purulent: thick yellowish-green discharge that often indicates infection.
  • Mucopurulent: a mix of mucoid and purulent nasal discharge
  • Viscous: sticky
  • Sanguineous: bloody
  • Epistaxis: a full-on nosebleed
  • Fetid: bad-smelling
  • Unilateral: discharge from one nostril
  • Bilateral: discharge from both nostrils

“Most snotty noses are bilateral but, as you go down the decision tree, that’s the first decision to be made because one-sided helps you locate it anatomically,” says Melissa Mazan, DVM, Dipl. ACVIM, professor of internal medicine, equine respiratory system, and lung function at Tufts University’s Cummings School of Veterinary Medicine, in North Grafton, Massachusetts.


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