Nobody likes a sinus infection. There’s pain from the pressure, congestion from the mucous, and it seems like it just won’t go away. Unfortunately for horses, their pain and congestion can be amplified by their relatively large sinus cavities that extend throughout their elongated heads. Horses can get sinusitis for a variety of reason but veterinarians classify them into two categories: primary and secondary. Primary sinusitis cases result from a bacterial and fungal infection that occurs after an upper respiratory tract infection. The nasal discharge generally has no odor and can generally be treated with antobiotics or antifungal therapy.

Secondary sinusitis is caused by a disease process from outside of the respiratory tract. The principal sources are tooth root abscesses, sinus masses, or skull fractures. Treatment for secondary sinusitis involves treatment of the underlying cause. ANTIBIOTICS ALONE ARE NOT A TREATMENT! We had to write that in all caps with the “!” because we frequently encounter cases where the owner or veterinarian has administered antibiotics, the symptoms have temporarily resolved and then reappeared, though now with antibiotic resistance. Sometimes this cycle has been repeated over the course of 6 months before the horse is referred to us only to find a fractured tooth, endodontic infection, a diastema with an oral-sinus fistula or a mass in a sinus cavity. This highlights the importance of having a veterinarian perform an in-depth, professional and thorough oral exam on a sedated horse.

Treatment of secondary sinusitis cases depends on the underlying cause. Our veterinarians. may recommend extracting a diseased tooth, performing a root canal, and/or a sinusotomy. A sinusotomy involves creating an opening through the skull bones into the sinus in order to remove a mass such as a cyst or ethmoid hematoma. These can be small holes that might be needed to flush warm sterile fluids through in order to lavage the sinus clear of inspissated pus, larger trephined holes that allow of to flush and remove larger chunks of tissue and pus, or bone flaps which are the largest of all openings for removing large masses.

Depending on the severity or duration of the disease we may need to flush the infected sinus for several days. Typically the longer the horse has been on antibiotics before the diagnosis, the more flushing and more expensive the treatment ultimately becomes.

When horses are sent home after a sinus surgery, they may have on a head bandage that needs to be kept clean and dry for the next week while the incisions heal. After 7 days, if the bandage is getting loose or soiled it can be removed and does not need to be replaced. Simply maintain good wound management by gentle cleaning of the incision and apply triple antiobiotic cream twice daily. Approximately 14 days after surgery, a veterinarian can remove the staples or sutures and the horse may be able to slowly resume its regular work depending on the case.