Dog Ear Infection Symptoms

A dog who constantly shakes his head may be battling an ear infection, especially dogs with drop ears.


It’s one of the most common questions we hear at a veterinary visit: Why is my dog shaking his head (or ears)? While inner-ear infections occur more in dogs with drop ears, like Cocker Spaniels, any dog can experience an ear infection. Causes can range from yeast to bacteria to mites or allergy, and we will explain the causes, treatments, and prevention here.

Signs of an ear infection include any of these symptoms:

  • Discharge from the ears
  • Odor coming from the ears
  • Redness in and around the ears
  • Rubbing ears on the ground or on furniture
  • Scratching his ears
  • Shaking his head

Infections can be in one or in both ears. Sometimes the ear canal is so swollen, the opening is obscured, making it difficult to see what is going on in the ear canal. This also makes getting topical medications in the ear more challenging.

Causes of Ear Infections

A proper diagnosis of ear discomfort will usually require ear cytology, a diagnostic test in which a sample of the ear discharge is smeared on a glass slide. The slide is then stained and examined under a microscope, so the laboratory can determine the cause of the ear infection. Different causes of ear infections have different treatments. Quick tip: Don’t clean out or treat the ears prior to the veterinary appointment! This could lead to misleading test results and an inaccurate diagnosis.

Ear infection causes in dogs include:

  • Yeast (Malassezia pachydermatis. This is a common cause of ear infections. While small numbers of yeast can normally be found in the ears and on the skin of dogs, overgrowth of this organism can cause problems. Yeast infections are treated with an anti-fungal medication.
  • Bacteria. Multiple species of bacteria can cause ear infections. These infections are treated with antibiotics. Occasionally, first-line antibiotic therapy is not effective, and in these cases, the ear discharge is cultured to find out what species of bacteria is causing the infection, and the bacteria’s sensitivity to multiple antibiotics is measured to determine the best antibiotic choice. What we often find in these cases is that the bacteria are resistance to one or more antibiotics. Knowing what the invading bacteria are sensitive to helps tailor the therapy to the specific medication that will work.
  • Ear mites (Otodectes cynotis). These are mites that live on the surface of the skin and can often be observed in an otoscopic exam. This ectoparasite is contagious via direct contact. There are multiple treatments for ear mites, including topical drops for the ear canal, one-time treatments that are administered directly into the ear canal, and other topical medications that also have action against fleas.
  • Allergy. Itchy ears also can be a consequence of an allergy. If the itchiness is caused by a seasonal allergy (atopy), controlling the itch during the season with either a steroid (oral or topical) or other anti-itch therapy (oral Apoquel, injectable Cytopoint) can bring relief.

Sometimes there are chronic ear problems that are non-seasonal, and these cases are often suspected to be related to dietary sensitivity (food allergy). The therapy of choice for a suspected dietary sensitivity is to do a hypoallergenic diet trial. The diet to try is one of two types: either a prescription hydrolyzed diet or a novel protein/novel carbohydrate diet (prescription or home cooked with recipe formulated by a veterinary nutritionist, to prevent contamination with other proteins that can often happen in over the counter foods and can confuse the results of the diet trial).

The trial would need to be at least 12 weeks in length and is very strict, which means no commercial treats, no table food, no counter surfing or garbage diving, no eating poop of a dog on a different diet.

During the duration of the diet trial, any other infections (see above) would need to be treated, as they will not magically go away without appropriate therapy.

When to See a Specialist

Ear infections should be treated under the direction of your dog’s veterinarian, or by a board-certified veterinary dermatologist.

Topical treatments are usually preferred, as the medication is placed in the site of the infection, and systemic side effects can be avoided. However, if the dog is too painful to treat topically, or is resistant to an owner administering medication at home, oral forms of the medications can be of benefit.

Follow-up visits to document success or failure of the treatment are important in managing each individual dog’s ear health. Don’t skip them! Ear infections left untreated or undertreated can result in chronic pain and inflammation, deafness, peripheral vestibular disease that can affect balance, or an aural hematoma, in which the ear flap (pinna) becomes distended as it fills with blood.

Aural hematomas, left to heal naturally, will result in scarring of the pinna that is similar to a wrestler’s cauliflower ear. American Cocker Spaniels are a breed that can develop ear canal issues even without infection.

When ear infections cannot be managed through medical therapy, total ear canal ablation (TECA) surgery may be considered. Even though this procedure essentially renders the dog deaf on that side (or totally deaf if both sides are treated), it provides relief to chronic pain and infection. The TECA surgery is also indicated if there are cancerous changes in the ear canal.


Clearly, ear infections are no fun for dogs or humans! Dog owners can help prevent ear infections from starting in the first place by using these simple guidelines:

  • Work with your dog to accept procedures. As soon as a dog is adopted, owners should start work on cooperative care training, in which the dog is taught not only to accept, but consent, to veterinary procedures. At the very least, owners should be able to touch the ears and look down into the ear canals to monitor for changes. Getting a dog to accept regular ear cleanings is also extremely helpful.
  • Consider using an ear cleaner with a drying agent in it for frequent swimmers. Often ear infections are more likely to set up after exposure of the ear canal to water. This is particularly notable for dogs who swim. If the moisture is left to evaporate naturally, this can set up a warm, humid local environment in the ear canal, which is an ideal condition in which bacteria and yeast can thrive. To speed up the evaporation of excess water in the ear canal, flush the ear canal after the last swim of the day with an ear cleanser, preferably one that has a drying agent in it.
  • Stick with any prescribed dietary plans. If a dog has been diagnosed with a dietary sensitivity (see allergy above), stick to the strict diet plan to avoid an allergic flare, which can take weeks or months to calm back down.