One-Sided Runny Nose: Is Sinusitis to Blame?

One-Sided Runny Nose: Is Sinusitis to Blame?

"Inflammation of the sinus, called sinusitis, is by far the most common cause for a unilateral (one-sided) nasal discharge in horses," explained Dixon.

Photo: Anne M. Eberhardt/The Horse

The common cold comes and goes with the seasons, and as winter approaches many horse owners are stuffing their barn coat pockets full of tissues to combat the perpetual runny nose that accompanies the ailment. Not unlike us, although not necessarily more commonly in the winter months, our horses can also come down with ailments that cause runny noses--typically with drainage from both nostrils. The causes of runny noses in horses are plentiful, but if a horse has a nasal discharge coming down only one nostril, it most likely due to some form of sinus disease.

"Inflammation of the sinus, called sinusitis, is by far the most common cause for a unilateral (one-sided) nasal discharge in horses," explained Paddy Dixon, MVB, PhD, MRCVS, professor of equine surgery in the University of Edinburgh's Division of Veterinary Clinical Sciences during his presentations at the 12th Congress of The World Equine Veterinary Association, held Nov. 2-6 in Hyderabad, India.

According to Dixon, some of the potential causes for the unilateral, white to green, thick mucus discharging from one or more of the seven paired sinuses in a horse include:

  • Primary sinusitis (no known etiology and the most common manifestation);
  • Dental disease (the tooth roots project into the maxillary sinus);
  • Cysts in the sinuses;
  • Neoplasia (tumors) of the sinuses (e.g., squamous cell carcinoma);
  • Fungal infection of sinuses (e.g., Aspergillus spp.);
  • Hemorrhagic polyps (e.g., progressive ethmoid hematomas) in sinuses; and
  • Trauma.

"Using an endoscope to directly and carefully examine inside the sinuses--a procedure called sinoscopy--is an important step in identifying the underlying cause of the sinusitis and will help guide treatment," said Dixon.

But this procedure should only be used if the sinuses are not totally filled with liquid pus, he noted. In those cases the sinuses will first have to be emptied by lavage (flushing) or suction of the exudate (pus, etc.) to allow inspection of their interiors.

Treatment will vary depending on the exact cause of the sinusitis but can include anything as innocuous as systemic antibiotics to more invasive techniques such as surgery. Veterinarians commonly create bone flaps to open the sinuses, which allows good visualization of the sinuses or might be performed to remove hardened accumulations of pus or intrasinus cysts, Dixon noted. Infected teeth are best extracted orally because there are less postoperative complications compared to repulsion of teeth (through the sinus), he added.

"Flushing the sinuses many times daily is commonly performed as part of treatment, to remove all discharges lying within them," Dixon concluded. "In over 95% of cases, the sinusitis will respond to these treatments, an exception being for (usually older) horses with malignant sinus tumors."

Stronger treatment is generally employed in these situations.

It's advisable for horse owners to take note of any nasal discharge and contact a veterinarian if a runny nose persists.

A full summary of the presentations titled, "Clinical and Diagnostic Aspects of Equine Sinusitis" and "Treatment of Equine Sinusitis" will be available for free on the International Veterinary Information System.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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