Primer on Tonsillitis

Written and reviewed by John A. Bukowski, DVM, MPH, PhD
and Susan E. Aiello, DVM, ELS

Dogs have two tonsils located in the back of the throat, where they act much like lymph nodes to combat throat infections.  

When the tonsils become inflamed, the condition is called tonsillitis.  It is most common in small breeds of dogs.

Tonsillitis can be caused by any infection or irritation of the mouth that allows bacteria to multiply and enter the throat.  

The most common cause is probably build up of bacterial tartar on the teeth and associated inflammation of the gums.  Most cases of tonsillitis are caused by an overgrowth of bacteria that are normally found in the mouth, which means that it is not usually contagious to other pets or people.

Dogs with tonsillitis tend to gag, as if something is in the throat, or to make exaggerated swallowing motions.  

Some dogs lick their lips repeatedly.  Most dogs with tonsillitis are reluctant to eat because swallowing is painful.  They may be hungry and go to their food bowl but then eat nothing or very little.  Activity level may be decreased, although tonsillitis does not usually cause a fever.

Tonsillitis is diagnosed by signs of infection and examination of the inflamed and enlarged tonsils in the back of the throat.  The tonsils are hidden in pouches, so they are difficult to see in healthy dogs.  In tonsillitis, the red and inflamed tonsils often “pop out” and can be seen by your veterinarian during an examination of the mouth.

Treatment involves antibiotics to combat the infection, followed by therapy to remove the source of infection.  

For example, a dental cleaning may be needed to remove built-up tartar and calculus.  Tonsillectomy is recommended only when the infection does not respond well to treatment, or if the condition recurs frequently.