Not long ago, as I was feeding my horses one evening, I noticed my gelding, Hershey had an extremely snotty nose–but only in one nostril. I knew that this wasn’t a ‘normal’ snotty nose, so I began researching the types and causes of nasal discharge in horses. As it turns out, discharge from one nostril can be the result of something fairly serious, so I called my vet. The vet didn’t seem to be as concerned as I was and told me to watch it for a few days. I did, and fortunately, it improved by the end of the week. Hershey had no other symptoms either, so I knew that was a good sign.
Nasal discharge in horses can come in varying colors and consistencies and can occur for a myriad of reasons. Sometimes, it’s the result of something minor and will subside on its own, but in other instances, it’s related to something much more serious and will likely need treatment.
First off, here are some terms related to nasal discharge in horses:
- Serous: clear and watery
- Mucoid: yellow and mucous-like
- Purulent: green-yellow, thick and pus-like (ewww!)
- Sanguineous: bloody
- Bilateral: occuring in both nostrils
- Unilateral: occuring in one nostril
Here are some common and a few not-so-common causes of nasal discharge in horses as well as some identifying factors:
- Allergies: bilateral, intermittent, serous to muco-serous discharge, may be accompanied by eye drainage;
- Wind or Dust Irritation: bilateral, mild, intermittent, serous discharge
- Viral Respiratory Infection (Influenza, Equine Herpes, Rhinotracheitis and others): usually bilateral, serous to muco-purulent, often accompanied by cough and possibly fever, can progress deeper into lungs and lead to secondary bacterial infection;
- Bacterial Infections (Strangles, Pneumonia): usually bilateral, purulent, often accompanied by depression, fever, cough, enlarged lymph nodes, and other serious symtoms;
- Heaves: bilateral, mucoid discharge, accompanied by cough, and increased respiratory rate;
- Sinus infection: unilateral purulent dishcharge, possibly foul-smelling, often occurs with tooth root infections, more common in older horses;
- Infected nasal passage mass/ Sinus cysts: unilateral possibly foul-smelling, purulent discharge, often causes facial deformity (swollen on one side of face)
- Guttural Pouch Empyema (bacterial infection): unilateral or bilateral, possibly foul-smelling, purulent discharge, usually occurs several weeks or up to a few months after Strangles or upper respiratory infection;
- Progressive ethmoid hematomas: unilataral and intermittant sanguineous discharge
- Foreign body in sinuses: (uncommon) unilateral muco-purulent discharge, sometimes sanguineous discharge;
- EIPH (Exercise Induced Pulmonary Hemorrhage): unilateral or bilateral, small amount of sanguineous discharge;
- Ethmoid hematomas: intermittant, small amount of unilateral or bilateral sanguineous discharge, possibly accompanied by cough or breathing abnormalities during exercise.
Something to keep in mind is whether or not your horse has recently been to a show, trail ride, etc. where he may have come into contact with an infected horse. If so, a viral infection may likely to be the cause of the discharge. If your horse has fever or other symptoms with nasal discharge, I wouldn’t hesitate to call your vet. Also, if discharge is sanguineous, obviously the horse needs to be evaluated as well.