Listen UP: The In’s and Out’s of Ear Infections


Ear infections are a frequent reason for veterinary visits in small animals. Because they are so common, it is easy to think they must be simple to diagnose and treat, but this is not always the case. It can be tempting to pick up an over-the-counter cleaner or try a home remedy found online. However, the best course of action is to work with a veterinarian in order to increase the chances of success.


What are the symptoms?

Symptoms of an ear infection include shaking of the head and scratching at the ears. Affected pets will often hold their ears abnormally. Increased discharge, redness, pain, and a foul odor from the ear are also commonly noted. These symptoms are related to overgrowth of bacteria, yeast, or a combination of the two within the ear.

What causes ear infections?

The majority of ear infections, especially chronic cases, have an underlying cause. Sometimes the cause is obvious, but, in many cases, it is more subtle. The most common cause is allergies — either food allergies, environmental allergies, or, rarely in our geographic area, fleas. Other causes include foreign material in the ear (such as grass awns) or parasites (such as ear mites).

Some pets also have predisposing factors that increase their risk for ear infections. These factors do not cause an ear infection on their own, but can make them more likely if an underlying cause is also present. These include conformation of the pet’s ears, such as narrow ear canals or hair in the ears; the pet’s lifestyle, including regular swimming, grooming, excessive ear care, or the presence of growths within the ear; or, other diseases that may affect the pet’s ability to fight infection.

How are ear infections treated?

If symptoms of an ear infection are noted, the first step is to visit a veterinarian to develop an appropriate treatment plan. This plan will be based on treating the underlying cause, so the veterinarian will perform a complete examination of the ear. For example, if a foreign body is identified in the ear canal, this will need to be removed to resolve the problem. The health of the ear drum is also evaluated. If the ear drum is ruptured, this can affect the safety of medications applied to the ear.

The veterinarian will discuss the pet’s prior medical history, especially regarding past ear problems and treatments. Many veterinarians also perform a diagnostic test called cytology, evaluating the ear debris under a microscope. This test allows the veterinarian to identify the type of organism causing the infection, such as bacteria or yeast, as well as look for other abnormalities, such as ear mites. Cytology helps to guide medication selection and monitor response to treatment.

Initial treatment generally involves cleaning the ear to remove excess debris. This debris interferes with medications penetrating the ear. Sedation is required in some cases to accomplish a thorough cleaning.

After the ear is cleaned, the infection is treated using medication, which is applied directly to the ear at home in most cases. Ear medications come in many forms, but the majority are combination products containing an antibiotic, an antifungal, and an anti-inflammatory. Significant infections may benefit from oral medications as well. It is important to understand the correct way to apply any ear medications dispensed by a veterinarian, so be sure to ask for proper instruction.

Why do ear infections keep coming back?

After treatment, it is important to follow up with the veterinarian for a medical progress examination. This is the case whether it is the pet’s first or fifth ear infection. Too often the infection appears to be gone when disease is still present deep in the ear canal. Once again, the ear will be carefully examined, and cytology may be repeated. The real challenge is to diagnose and treat the underlying cause to prevent problems from recurring and minimize on going ear inflammation, pain, and damage. It is important to continue to work with a veterinarian and to develop a plan for long term prevention, such as weekly ear cleaning, once the acute infection is eliminated.

Rachel Walton received her Doctor of Veterinary Medicine from Colorado State University in 2007. She is an associate veterinarian at University Veterinary Hospital & Diagnostic Center in Salt Lake City.

By: Rachel Walton, DVM