Stan Wood, DVM, Diplomate ABVP

Specialist in Canine & Feline Practice

Tonsillitis in Dogs

Since dogs have tonsils, it is possible for them to have tonsillitis.

The tonsils are much like lymph nodes (lymph glands). There are two of them, and they are located in the back of the throat. When they are normal, they are not easily seen because they reside in crypts (pouches). Like lymph nodes, their job is to fight infection. When they are doing this, they often become infected themselves and will enlarge.

Prevalence

Tonsillitis is relatively common in small breeds of dogs and much less common in large dogs.

Causes/Transmission

There are certain conditions known to cause tonsillitis. Chronic vomiting, a chronic productive cough, sinus drainage, foreign bodies, trauma, and chronic disease in the mouth will allow bacteria to infect the tonsils. The main cause of chronic disease in the mouth is tartar on the teeth and the infections that are associated with it. Occasionally, primary tonsillitis (no underlying cause) will occur; this is almost always in young dogs of the small breeds.

Clinical Signs

When the tonsils enlarge, they are usually quite painful. The dog may have a red, irritated throat (pharyngitis), along with the tonsillitis. This causes the dog to gag, as if something is in the throat, or to make exaggerated swallowing motions. Some dogs appear to be licking their lips repeatedly. Most affected dogs are reluctant to eat because of the pain associated with swallowing. They may be hungry and go to the food bowl but refuse to eat. Many dogs with tonsillitis are not as active as normal, but they usually do not have fever. This is the one characteristic that differs markedly from people with tonsillitis.

Diagnosis

Swollen, red tonsils that are out of their crypts are easily seen in the back of the throat if the dog will permit its mouth to be opened widely.

Treatment

If an underlying source of the infection can be found, it must be treated. Antibiotics are given for 2-3 weeks in an effort to rid the tonsils of infection and to treat any other infection that may be present. If the teeth are tartar-laden and infected, they must be cleaned.

Removal of the tonsils is not the first approach to treatment, but it can become necessary if there is poor response to treatment or if tonsillitis becomes a recurring condition. This is more likely to happen in small breeds of dogs.

Prognosis

The prognosis is dependent upon the underlying cause and is determined on an individual basis. In young dogs, idiopathic tonsillitis often resolves on its own or will respond to antibiotics.

Transmission to Humans

Most cases of tonsillitis are caused by bacteria that normally are found in the mouth of dogs and humans. Therefore, it is not contagious unless it is caused by an unusual bacterium.

Streptococcus pyogenes, the cause of “strep throat” in humans does not cause tonsillitis in dogs or cats. However, dogs and cats can acquire a transient infection with this bacterium when they are in contact with a human with strep throat. Although they do not get strep throat, they may harbor the bacterium and serve as a source of it for other human infections. Therefore, it is suggested that dogs be treated when family members have strep throat, especially if recurring infections occur in the household.