It is not uncommon for us veterinarians to get a call about a horse with a snotty nose. A snotty nose can be due to variety of causes, and we typically ask a couple questions that may point us in the right direction.

To begin, does your horse feel OK otherwise?

A horse with a snotty nose who appears lethargic/doesn’t want to eat and/or has a fever (rectal temperature > 101.5F) could indicate that whatever is causing the snotty nose is affecting the horse systemically. Not every snotty nose requires immediate veterinary intervention, but a horse with a snotty nose who feels bad should be seen by a veterinarian in the very near future. So, what are the things we are worried about? Pneumonia (an infection in the lungs) is one of our great concerns. Pneumonia can become life-threatening and require intensive, long-term treatment. The sooner we see these horses, the better their prognosis. In adult horses, pneumonia can occur after hauling long distances (> 6 hrs), an episode of choke, general anesthesia, or secondary to an upper respiratory infection like Equine Influenza.

Has your horse been around any new horses?

There are a variety of infectious upper respiratory infections that are typically transmitted from horse to horse. With many of these infections, you may find that your horse develops a snotty nose a couple days after interacting with new horses. When we ask about your horse’s interaction with new horses, we also need to know if your horse has been to a show/event, recently traveled, or was recently purchased from a sale barn? We are essentially trying to determine if your horse could have been exposed to one of these infectious agents. In addition to a snotty nose, you may also notice coughing, lethargy, and/or a fever. So, what are some of these infectious diseases?

  • Equine Influenza Virus
  • Strangles – streptococcus equi equi
  • Equine Herpes Virus
  • Equine Rhinitis Virus
  • Equine Adenovirus
  • Streptococcus zooepidemicus

Not all of these above diseases cause severe disease or even require treatment. But recognizing their risk may help to reduce spread to new horses. If we are suspicious of an infectious respiratory infection, we will often swab the nose and submit to a laboratory for testing.

Does the snot smell bad? And is it coming from one nostril or both?

Horses have what we call hypsodont teeth, which means they are tall and continue to erupt as the horse ages. So, as you can imagine, the cheek teeth of horse have very long roots. Some of these roots live within the sinuses of the head. If a horse develops an infection in one of these teeth than it may also result in a sinusitis (sinus infection). An infection in a sinus often leads to nasal discharge as it drains. This discharge is usually very foul in odor and only affecting one side of the head (left versus right). We can use radiographs (x-rays) to diagnose infection in the sinus and treatment typically involves removal of the affected tooth and flushing of the sinus.

Is there feed material in the snot?

Sometimes horses can suffer from esophageal obstruction which we refer to as “choke”. These horses don’t typically have an obstruction that affects their ability to breath like we think about in humans who choke. So don’t worry, your horse can breathe. What typically occurs, is some type of feed material has blocked the esophagus. As a result, the horse can’t pass feed through their esophagus so saliva and feed material will overflow from the esophagus and come out the nose and look like slimy snot with feed material. Unfortunately, this overflow can also find its way into the trachea which will cause coughing and increase the risk of aspiration pneumonia. Horses can choke on just about anything, but we often find that dry Equine Senior, dry hay pellets, dry alfalfa cubes, dry beet pulp, or large treats are usually to blame. Horses with bad dentition can often be at risk of choke from hay as well. We usually consider choke an emergency because the quicker we can resolve the esophageal obstruction the less risk for your horse to develop pneumonia. There are some other causes for horses to have feed material around the nostrils but choke is the most common.

Is your horse in an environment with a lot of allergens?

Horses suffer from allergies just like us. We often find that horses who live in barns with poor ventilation, eat from round bales, and/or are ridden in dusty arenas can suffer from allergic airway disease more than others. Sometimes these allergies only affect the upper airway and may produce some coughing and a little bit of snot from both nostrils. Other times, the lower airways (lungs) can become affected and result in equine asthma which may also cause a snotty nose. Asthma is a little different in horses than in humans. Horses don’t typically suffer from “asthma attacks” and unless affected by severe equine asthma, horses don’t typically have trouble breathing at rest. While most horses that suffers from allergic airway disease are usually happy and healthy otherwise, those with equine asthma may have some degree of exercise intolerance. Treatment for allergic airway disease usually involves environmental management and reducing exposure to allergens. In some cases, horses with equine asthma will require systemic or even inhalant medications.