A vet inspects a rabbit's ears.

Understanding and Preventing Pet Ear Infections

In addition to being incredibly frustrating, ear infections can be very painful for pets. C Whether you have a dog or a cat, treatment for pet ear infections can be challenging at times, since many animals are resistant to topical ear medications and-consistent cleaning of their ears. It’s important to understand all the different factors involved in pet ear infections to help reduce the rate of recurrence for your pet.

The Vicious Cycle of Pet Ear Infections

Ear infections in pets, also called Otitis Externa, can lead to head shaking, non-stop scratching, bad odors, and painful ears for your furry friend. Beyond that pet ear infections can also mean multiple trips to the vet should the issue become chronic. Chronic ear infections can affect a pet’s quality of life and potentially lead to hearing loss.*

Ear infections are often a frustrating cycle of prolonged treatment followed by a short period of relief and then, ultimately, a recurrence of the issue. In order to break out of the treat-and-repeat struggle, you must have an understanding of all the potential factors that may be contributing to ear infections in your pet. Factors leading to the development of ear infections are generally broken down into four categories: primary, secondary, predisposing, and perpetuating factors.

Primary Factors for Pet Ear Infections

Primary factors are causes that can actually trigger the development of an infection in a normal ear. The most common primary factor is an underlying allergic disease. The main allergies seen in dogs and cats that contribute to ear infections are atopy (environmental allergies), cutaneous adverse food reactions (food allergies), and flea allergies. Immune mediated diseases and hormonal changes, like hypothyroidism, may also trigger recurrent ear infections. Less common primary triggers include parasites, such as ear mites, or foreign bodies, such as fox tails or tumors. Treatment for ear infections should focus on diagnosing and controlling the primary factor to help prevent reoccurrence.

Secondary Factors

Secondary factors can lead to disease in abnormal ears, but are generally not the sole trigger in an ear infection. These can be infectious triggers, like bacteria or yeast, or they can be reactions to topical medications or excessive moisture as a result of over-cleaning. The use of cotton swabs can also cause trauma to the canal and result in the development of an ear infection. Often the treatment of ear infections is only focused on the secondary cause, which is why there is short-lived improvement when only secondary factors are managed.

Predisposing Factors

Predisposing causes are factors that decrease response to treatment, help create an environment that allows other factors to thrive, or occur as a result of chronic ear inflammation. The most common predisposing factors are conformational, including excessive hair in the ear canals, narrowed canals, or pendulous ear flaps. There is a lot of misinformation about factors such as hair in the ears or swimming being a cause of ear infections. Plucking ear hair is controversial, as it can lead to trauma and inflammation in the canal, increasing the risk of developing an infection. Concerning swimming, it cannot cause an ear infection by itself, but excessive humidity or moisture in the canals can make it more challenging to control the primary inflammatory cause. Another common predisposing cause of ear infection are masses in the ear canal, which, even if they’re benign, can cause obstructions that prevent the normal cleaning mechanisms of the ears. This can lead to the build up of moisture and debris, making an infection more likely. When it comes to predisposing factors, it is important to remember that these factors won’t cause ear infections, unless there is also a primary factor involved.

Perpetuating Factors

The final category of factors contributing to pet ear infections are perpetuating factors. Perpetuating factors are causes that are generally anatomical and present prior to the onset of the ear infection itself, but will ultimately contribute to the persistence of problem within the ear. These factors include a ruptured eardrum, swelling or narrowing of the ear canal, excessive proliferation of the glands, chronic middle ear disease, or diseases that affect the normal skin lining the canals (keratinization disorders). Perpetuating causes are often more common with chronic ear disease. Prolonging management of all the other causes contributing to ear infections can lead to irreversible changes of the ear canal. Common end stage changes in the ear canal can be chronic stenosis (narrowing) of the canal and mineralization of the ear canal.

Treatment for Pet Ear Infections

Although your primary veterinarian can manage and treat most ear infections, for more challenging cases you may be referred to a specialist. A veterinary dermatologist specializes in animal ears and allergies can better manage chronic pet ear infections. The main goal is to diagnose the underlying triggers and formulate a treatment plan to help decrease the frequency and severity of ear infections for your pet.

Ultimately, when it comes to ear infections, there are many different factors at work and getting to the root of the issue will help you and your pet successfully escape the treat-and-repeat cycle.

* Miller, WH., Campbell, KL., Griffin, CE. (November, 2012). Diseases of the Eyelids, Claws, Anal Sacs, and Ears. Mueller and Kirk’s Small Animal Dermatology 7th edition. Retrieved November, 2019