An ear infection is inflammation or infection of the ear due to bacteria, yeast, or mites. Ear infections are more common in pets that have floppy ears that do not receive adequate ventilation. Certain breeds such as hounds, retrievers, and spaniels are more prone to ear infections for this reason. Bacterial and yeast ear infections thrive in a warm, moist environment making ear infections more common in dogs who do a lot of swimming, get water in their ears during bathing or have their ears licked by another pet. Mites are more common in cats than dogs, but can cause infection in either species. Most ear infections are the product of an underlying cause which should always be addressed.
Symptoms of an ear infection include dark debris in the ear canal, redness in or around the ear, inflammation in or around the ear, itching the ear, head shaking, pawing at the ears, pain around the ears or an unpleasant odor.
When you bring your pet in with a possible ear infection, the veterinarian will examine both ears. This can include looking at the pinna of the ear as well as the ear canal and tympanic membrane (ear drum) with an otoscope. In some cases the doctor will collect a sample from the ear using a cotton swab and will make a slide for examination under the microscope. This allows us to determine what organism is causing the infection, which allows for proper treatment. Repeat or especially severe bacterial ear infections occasionally need to be cultured at the laboratory in order to determine the exact bacterium responsible for the infection.
The successful treatment of most ear infections depends upon determining the underlying cause of the ear infection. The following conditions can all cause recurring ear infections:
Allergies: the most common cause of recurring ear infections, food or environmental allergies can predispose your pet to recurrent and chronic ear infections. A hypoallergenic food trial or testing for environmental allergies is necessary for diagnosis.
Hormonal disease: diseases such as hypothyroidism can make your pet more prone to ear infections. Other hormonal diseases can suppress the immune system and make your pet more susceptible to infection. Blood work is necessary to diagnose these diseases.
Foreign objects: objects lodged in the ear canal, such as dried wax or grass can act as a focus of infection
Middle ear infection: when an infection is chronic it can penetrate through the eardrum into the middle ear. Sedation and sometimes ear radiographs are necessary to identify this problem. Oral antibiotics, flushing under general anesthesia, and surgery may be necessary to treat middle ear infections.
Abnormal ear conformation/hair: narrow ear canals, long ear flaps, or hair growing in the ear canal can cause moisture and wax to accumulate in the ear canal leading to infection. Appropriate grooming and use of a drying agent in the ear can help.
Tumors/polyps: masses in the ear can block the canal, leading to infection and preventing medication from penetrating well. Surgery may be needed to remove growths.
Treatment of an ear infection is based upon the organism causing the infection. Many ear infections are treated using a topical medication. The ointment or drop is instilled into the ear canal 1-2 times daily for a period of 7-21 days. Some common topical ear medications are Animax, Mometamax, Baytril Otic, and Tresaderm. Topical medications are often prescribed along with an appropriate ear cleaner such as TrizChlor, TrizUltra or T8 Keto.
In some severe cases an oral antibiotic or oral steroid may be prescribed. It is always important to treat exactly as directed by your veterinarian. Treating for the indicated amount of time and then having a veterinarian recheck your pet’s ears is essential. All ear infections should be rechecked before discontinuing treatment. The recheck allows the doctor to determine if the medication has worked and if further treatment is necessary. Chronic ear infections can often take weeks to completely eradicate.
Remember that your pet’s ear canal is L-shaped and has a vertical and a horizontal canal. It is VERY IMPORTANT that you instill enough medication in the ear to coat both the external vertical canal and the internal horizontal canal. To properly clean the ear canals apply a large amount of cleaner into the ear canal with a cotton ball or directly from the bottle. Massage the base of the ear and then allow your pet to shake its head. Clean loose debris from the ear using cotton balls and cotton swabs. If an ear infection is not treated or not treated properly it is important to remember that it is an uncomfortable, itchy, and often painful condition for your pet. Left untreated, ear infections can lead to a permanent thickening of the ear pinna and canal, ruptured ear drums leading to hearing loss, and ear hematomas (where the ear pinna becomes filled with blood, often caused by head shaking).