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Chronic Otitis in Dogs: Causes & Prevention

Ear infections can cause uncomfortable symptoms and may recur. Here, our Crystal Lake vets discuss the impact of chronic otitis in a dog’s ear, including the signs, causes, and how to prevent it.

An Overview of Chronic Otitis in Dogs

Chronic otitis (ear infection) is a disease of the dog's ear canal that can be externa (of the outer ear canal only), media (involving the middle ear), or interna (involving the inner ear and associated structures). It primarily affects the external ear canal and, to a lesser extent, the middle and inner ear, making it a dermatologic condition.

Causes & Pathogenesis of Chronic Otitis in Dogs

An ear infection is typically caused by irritation to the skin lining the ear canal, which causes inflammation, along with yeast and bacteria overgrowth. This triggers itching and further inflammation, which leads to self-trauma due to scratching.

Any dog, regardless of ear shape, water exposure, or the amount of hair inside the ear canal, can develop an ear infection. In most cases, the underlying cause of the irritation is allergic or unrelated to the shape of the ear and moisture. Environmental allergies and food allergies can also cause an allergic skin reaction leading to otitis externa.

Other, less common causes of otitis externa in dogs include:

  • Polyps or other growths in the ear canal
  • Foreign bodies in the ears, including dirt, sand, or plant material (foxtails and grass awns)
  • External parasites (like ear mites)

Chronic otitis is a painful condition caused by inflammation, infection, and thickening of the ear canal's tissues. This causes narrowing of the ear canal, ruptured eardrums, and debris and infection within the middle ear. Scar tissue blocks the canals over time, preventing medications from reaching the diseased portions of the canal and preventing the natural sloughing of skin cells, sebum (wax), and hair from the canal.


Exposure: Exposure to irritants, parasites or illness can lead to irritation in the ear.

Adhesion: Damage caused by irritation in the ear tissue creates an opening for bacteria and yeast.

Invasion: The bacteria or yeast enter the body and begin to multiply.

Infection: The development of an ear infection (otitis) occurs.

Transmission: While otitis itself cannot be transmitted, illnesses or parasites related to otitis can be.

Another great example of why preventive care is so important is that colds and other illnesses can be spread even when there are no obvious symptoms, potentially leading to ear infections.

Signs of Canine Chronic Otitis

Chronic otitis is a frustrating disease for both owners and veterinarians. Still, it is far more uncomfortable for patients due to the pain and nagging itchiness that these ear infections cause.

The clinical signs of otitis you may notice in your dog will depend on the severity of the inflammation, but may include:

  • Shaking the head or rubbing the head and ears on the floor or furniture
  • Scratching at the ears
  • Discharge from the ears, which can sometimes have a foul odor
  • Redness of the ear canal and earflap (the ears may also feel warm when touched)
  • Ear hematoma, evidenced by a grossly swollen earflap
  • Aggression whenever you try to touch the head or ears

Progression of this infection into the middle and inner ear can result in even more severe clinical symptoms, such as head tilt, incoordination, inability to stand or walk, hearing loss, and intense, unrelenting pain. If the otitis is severe or chronic, the outer ear canal can thicken and become deformed, making it difficult to clean the ears.

Chronic otitis is typically diagnosed based on a history of previous ear infections and physical examination findings. Redness, inflammation, discharge, and other changes within the ear will readily indicate the presence of an ear infection, but the difficult part will be determining what types of microorganisms are exploiting the dog's inflamed ears and what is causing the inflammation in the first place. Specialized diagnostic testing, like otic cytology, will likely be recommended in these cases.

Otitis in Dogs: Treatment Options

Your vet's recommendations for treating otitis in dogs will depend on the cause of the infection. Your vet will address the components, whether bacterial or fungal, as well as the inflammation, with antibiotics.

Treatment for dogs experiencing otitis includes:

  • Cleaning the Ear Canal – A thorough ear canal cleaning will remove accumulated debris. If the otitis is painful and/or a lengthy process, cleaning should ideally be done while the pet is sedated or anesthetized. Otoscopy is frequently recommended as a tool in this process.
  • Topical Medication – Bacteria, yeast, or mites may be treated using topical medication in the form of ear drops or ointment. Antibiotics, antifungals (to kill yeast), anti-inflammatory drugs (such as cortisone), and topical anesthetics are examples of these.
  • Antimicrobial Medications – In some cases, such as when the eardrum is ruptured, systemic antimicrobials (antibiotics administered by mouth or injection) are indicated. Antibiotic therapy should ideally be based on the results of culture and sensitivity testing.
  • Pain Management – To alleviate pain, redness, and swelling, systemic anti-inflammatory medications such as corticosteroids are sometimes used. Antihistamines may be prescribed as well.

To stop this disease, the underlying illness must be treated. Treatment options may range from mass removal and mite killers to diet changes and allergy injections. In difficult cases, surgical intervention may be required.

If your dog suffers from chronic otitis or has severe symptoms, your veterinarian may refer your pup to a specialist. Our internal medicine department at CASE Hospital is equipped to handle such cases.

Preventing Otitis in Dogs

Prevention is typically better than treatment when it comes to ear infections. By keeping your dog's ears clean and dry you can help reduce the occurrence of ear infections. Talk to your primary vet about the best cleaning solution for your pup and take the time to give your dog a weekly ear cleaning. It is also a good idea to dry your dog's ears if they have spent time in the water.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Is your dog experiencing the signs of a serious ear infection? Ask your primary care vet about a referral to our specialty veterinary hospital in Crystal Lake.

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Companion Animal Specialty and Emergency Hospital is accepting new patients! Our specialists and experienced emergency veterinarians are passionate about restoring good health to animal companions in Crystal Lake.

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