Ear infection in dogs 

Symptoms and treatment of ear infections in dogs

Ear infections in dogs (otitis externa) are a common reason for veterinary visits. The condition can cause significant itching and pain, and recurring or long-term ear problems can lead to chronic changes in the ear canal. Good treatment is therefore not only about treating the bacteria or yeast, but also about finding out why the ear has become inflamed.

At A-Vet we examine both the dog's general health, the skin and the ear itself. Samples from the ear canal are usually examined under a microscope, and the treatment is adapted to the findings in the individual dog. If necessary, we can perform a thorough ear irrigation with a video otoscope under full anesthesia and follow up the treatment with check-ups and new cytological examinations.

What is ear infection in dogs?

The dog's ear consists of the outer ear, the middle ear, and the inner ear. The outer ear includes the earlobe and an L-shaped ear canal with a vertical and a horizontal part before the eardrum. The length of the ear canal varies between breeds and individuals. The ear canal is lined with skin, and disease of the outer ear is therefore closely related to the health of the skin.

A healthy ear canal has a natural self-cleaning mechanism called epithelial migration. Skin cells and earwax are gradually transported outwards into the ear canal. In the event of inflammation, this mechanism can be disrupted, and the ear canal can become red, painful and swollen, producing more discharge. Swelling, pain and discharge can also make it difficult to examine the entire ear canal and eardrum with a regular otoscope.

Acute or chronic ear infection?

How long the inflammation has lasted, and whether the dog has had ear problems before, is important for both diagnosis and treatment.

Acute ear infection

In acute ear infections, the dog may experience itching, redness and pain in the ear. There may be more earwax or discharge than normal, and many owners notice that the ear smells different. The dog may shake its head a lot, scratch itself or react when the ear is touched.

Chronic or recurring ear infection

With prolonged or recurring ear infections, changes can develop that make the ear more difficult to treat. The skin in the ear canal can thicken, the ear canal can become narrower (stenosis), and normal ventilation and self-cleaning can be impaired. Such changes can in turn contribute to the maintenance of the inflammation, and chronic ear infections can have a significant impact on the dog's quality of life.

Symptoms of ear infection in dogs

One or more of the following symptoms may indicate an ear infection:

• The dog often shakes its head.
• The dog scratches its ear or rubs its head against the floor or furniture.
• Increased amount of earwax or yellow, brown or dark discharge.
• Abnormal or strong odor from the ear.
• Redness or swelling in the ear canal or earlobe.
• Pain or discomfort when the ear is touched.
• Bloody ears (othematoma), which can occur after severe itching or head shaking.

Signs of disease in the middle ear or inner ear

In chronic or severe ear disease, the middle ear, and in some cases the inner ear, may also be involved. Signs that differ from normal itching and irritation should be investigated promptly by a veterinarian.

• Crooked head position.
• Balance disorders or unsteadiness.
• Involuntary eye movements (nystagmus).
• Reduced hearing.
• Facial paralysis (facial paresis).
• Signs of Horner's syndrome, including prolapse of the third eyelid and smaller pupil on the affected side.

When should a dog be examined by a veterinarian?

Contact your veterinarian if your dog has obvious itching, pain, discharge, bad odor, or repeated ear problems. If your dog has a tilted head, balance problems, nystagmus, facial paralysis, or severe pain, your dog should be examined promptly.

It is beneficial to examine the ear before it becomes severely swollen and painful. Early examination also makes it easier to identify any underlying cause.

Why do dogs get ear infections?

Bacteria and yeast can be important in ear infections, but they are often secondary to another cause or to changes in the environment of the ear canal. Therefore, to reduce the risk of recurrence, the veterinarian must consider more than the infection itself. The causes and factors that contribute to ear infections can be divided into four groups:

Predisposing factors

Predisposing factors do not necessarily cause ear infections on their own, but can make the ear canal more susceptible. These can include narrow ear canals, excessive moisture, or irritation from excessive cleaning or hair pulling.

Primary causes

These are diseases or influences that can initiate inflammation in an otherwise normal ear canal. Common examples are:

• Hypersensitivity
• Foreign objects in the ear canal, such as plant parts.
• Parasites, including ear mites.
• Certain immune-mediated or other skin diseases.
• Polyps or tumors.

Secondary factors

When the environment in the ear canal is changed by inflammation, yeasts such as malassezia and various bacteria multiply. This overgrowth contributes to discharge, odor, pain and further inflammation and must be treated while the underlying cause is assessed.

Maintaining factors

Long-term inflammation can lead to thickening of the skin, scar tissue, narrowing of the ear canal, and middle ear disease. These changes can cause the problem to persist even if the original trigger is under control.

Also read: What do I do if my dog ​​scratches his ear?

How we diagnose and treat ear infections at A-Vet

The course of treatment is tailored to the dog and the findings of the examination. Some dogs have an uncomplicated, acute ear infection, while others need a more extensive examination and more checks. Roughly speaking, a course of treatment with us may look like this:

First visit: examination, cytology and relief

At the first consultation, we start with a clinical examination of the dog. We assess the skin in general and examine the ears in particular, including looking for signs of allergic skin disease or other conditions that may be relevant to the ear problems.

The ear canal is examined with an otoscope as far as possible, and we usually take samples from the ear for cytology. During a cytological examination, we look at the material from the ear canal under a microscope and assess, among other things, yeast, bacteria and inflammatory cells. This provides important information about what is going on in the ear and how the treatment should be planned.

A very painful, inflamed or swollen ear may be difficult to examine and clean thoroughly on the first visit. In such cases, we often start treatment to reduce inflammation, itching and pain before further examination or ear irrigation.

In the case of recurrent ear infections, we also assess possible underlying causes. If a food reaction is suspected, a controlled elimination diet may be necessary. Blood tests are not used to diagnose or rule out food allergy, but may be relevant if we suspect other diseases, such as low metabolism.

Next visit: ear irrigation with video otoscope if needed

Not all dogs need ear irrigation. If the ear canal contains a lot of secretions or material, the eardrum is difficult to assess, or the ear disease is more extensive, we may recommend a thorough ear irrigation with a video otoscope.

At A-Vet, thorough ear irrigation with a video otoscope is performed under full anesthesia, with ventilation and continuous monitoring throughout the procedure, and requires at least two people to be present. The procedure typically takes between 1 and 2,5 hours, depending on the extent of the cleaning. The anesthesia keeps the dog completely still, while the veterinarian can work in a controlled and gentle manner in a sensitive and often painful ear canal.

We use a Karl Storz video otoscope, which provides a magnified image of the ear canal and eardrum on a screen. Via the instrument's working channel, we can rinse the ear canal with temperate physiological saline (0,9%) — typically between 500 and 2500 ml depending on how much cleansing the ear needs — aspirate rinsing fluid and secretions, and if necessary remove wax, debris or other material under direct visual control. Images from the examination can be stored in the patient's record.

If otitis media is suspected, further diagnostics may be necessary. In selected cases, the veterinarian may take a sample from the middle ear through the eardrum (myringotomy) for cytology and possibly bacterial culture.

In the video you can see how the ear canal can be rinsed and suctioned clean under direct visual control. Via the working channel we can also use small instruments to remove material that is in the ear canal.

Further visits: check until the ear is under control

Cleaning and treatment between checks

Not all dogs need video otoscopic ear irrigation. How the ear should be cleaned and treated is assessed based on findings from otoscopy and cytology, the degree of inflammation and pain, and whether the eardrum can be assessed. In some treatment courses, cleaning is performed at the clinic, and the owner may be instructed not to clean or treat the ear at home between check-ups.

Post-treatment check-up

After treatment, we schedule follow-ups based on the extent of the ear infection and how the dog is responding. In the case of complicated or recurring ear infections, we often monitor the dog more closely in the initial period. At the check-ups, we assess symptoms and re-examine the ear canal. If necessary, new samples are taken for cytology, so that we can compare with previous findings and assess how the inflammation and microbial overgrowth are responding to the treatment.

The fact that the dog itches less or that the ear looks better does not necessarily mean that the treatment is finished. In complicated cases, we therefore use both the clinical examination and cytology when assessing whether the result is satisfactory, and continue the follow-up until we are satisfied with the development. The number of checks and total treatment length are adapted to the individual dog.

How much the owner should clean or treat the ear at home varies between patients. In some treatment courses we prefer that the ear is not treated at home between check-ups, while other dogs are prescribed local or systemic treatment to use at home. Therefore, follow the treatment plan you receive for your specific dog.

Complications of long-term ear infections

Long-term inflammation can lead to thickening and scarring of the ear canal. Over time, the ear canal can become so narrow that ventilation, natural self-cleaning, examination and local treatment become more difficult. In severe chronic cases, the changes can become permanent, and surgical treatment may be necessary.

Pseudomonas and other complicated bacterial infections

In chronic or previously treated ear infections, rod-shaped bacteria may occur, such as: Pseudomonas aeruginosaSuch infections can be challenging to treat, partly due to antibiotic resistance and the bacteria's ability to form biofilms.

Bacterial culture and susceptibility testing are not necessary for all ear infections, but may be relevant for complicated or treatment-resistant infections, when otitis media is suspected, if systemic antibiotic treatment is being considered, or when the findings otherwise indicate that the treatment needs to be investigated further.

Otitis media

Middle ear inflammation (otitis media) is particularly relevant in chronic or recurrent ear disease and can be an important reason why treatment does not provide lasting effect. If middle ear disease is suspected, more extensive diagnostics and treatment may be necessary.

How to prevent ear problems

• Do not clean healthy ears unnecessarily. A healthy dog's ear does not necessarily need regular cleaning, and excessive cleaning can disrupt the ear's natural physiological processes and self-cleaning mechanism.
• Follow your veterinarian's advice if your dog needs ear cleaning. The need varies between dogs and between different ear diseases.
• Avoid unnecessary hair pulling in the ear canal. Napping can irritate the skin and should be considered individually.
• Be careful after bathing and swimming. Humidity can contribute to problems in predisposed dogs.
• Get to know your dog's normal ears. This makes it easier to detect changes in odor, discharge, redness, or sensitivity early.
• Get recurring ear problems investigated. Repeated episodes may be a sign of an underlying illness that needs to be addressed to achieve lasting control.

Diagnosis of ear infection at A-Vet

If you suspect an ear infection in your dog — pain, itching, bad odor, discharge or recurring ear problems — we can examine both the ear itself and possible underlying causes. If necessary, we have equipment for video otoscopy, thorough ear irrigation and further follow-up with cytology.

Also read about ear infections in cats.