Ear Infections in Dogs and Cats: Understanding and Managing Common Causes

Ear infections are a prevalent and often frustrating problem for both pets and their families. These infections, which can be painful for pets, frequently require repeated veterinary visits and treatments, leading to significant emotional and financial stress. Many dogs and cats, particularly those with chronic or recurrent infections, experience persistent discomfort due to this condition. This month, we’ll explore the anatomy of the ear, common causes of infections, symptoms to watch for, and ways to manage and prevent these issues effectively.

Understanding Ear Infections: Key Terms

When discussing ear infections in pets, veterinarians often use specific terms to describe the location and severity of the infection:

• Otitis Externa: Inflammation and infection of the outer ear canal, the most common form of ear infection in both dogs and cats.
• Otitis Media: Inflammation affecting the middle ear, often resulting from the spread of infection from the external ear.
• Otitis Interna: Inflammation of the inner ear, which can affect balance and hearing and, if untreated, lead to severe complications such as neurological issues.

Anatomy of the Ear

To understand how infections develop, it’s helpful to know a bit about the anatomy of a pet’s ear. The ear canal in dogs and cats is shaped like an “L,” with both vertical and horizontal components. This structure can make it difficult for debris, moisture, and infection-causing organisms to escape, contributing to the risk of infection. 

The eardrum (tympanic membrane) separates the external ear canal from the middle ear, while the inner ear houses delicate structures responsible for hearing and balance. The condition of an eardrum can influence how infections spread.  Understanding whether or not an eardrum is ruptured is an important part of selecting safe and effective ear medications. 

Additionally, an auditory tube connects the middle ear to the back of the throat.  Its primary role is to equalize air pressure on either side of the ear drum and drain any fluid that accumulates in the middle ear.  This process is crucial for maintaining normal hearing and protecting the middle ear from infections. 

In cats, benign polyps can obstruct the external ear canal, or the auditory tube.

Symptoms of Ear Infections

Recognizing the signs of an ear infection early can help prevent complications. Common symptoms include:

• Persistent scratching of the ear
• Head shaking or tilting
• Foul odour from the ear
• Discharge from the ear, which may be brown, yellow, or bloody
• Redness or swelling inside the ear canal
• Texture changes in the skin inside the ear (thickening, scaling)
• Behavioural changes such as crying, hiding, or aggression when the ear is approached
• Hematomas (swelling filled with blood) caused by head shaking

In severe cases, infections can affect the middle or inner ear, leading to symptoms like dizziness, loss of balance, or hearing loss.

Causes of Ear Infections

The causes of ear infections vary by age group and species, and understanding the underlying issue is critical for effective treatment.

Juveniles

In puppies and kittens, ear infections are often caused by parasites, particularly ear mites (Otodectes cynotis), which are highly contagious and cause intense itching. Dark, coffee-ground-like discharge is a hallmark of ear mite infections. Other causes include foreign bodies like grass seeds, or congenital issues that affect the ear canal's shape.

Adult Dogs

The most common cause of ear infections in adult dogs is allergic skin disease, such as atopic dermatitis or food allergies, which can lead to chronic inflammation of the ear canal. Allergic skin disease increases the heat and moisture within the ear canal, making the area more favourable for bacterial growth.  Because of this, bacterial and yeast infections often develop secondarily to allergic inflammation. Dogs with certain ear conformations—such as breeds with floppy ears like Dachshunds, narrow canals like Cocker Spaniels, or hairy ear canals like Poodles—may be more prone to infection due to reduced airflow and trapped moisture and wax in the ear canal. Grooming practices such as overuse of cleaners or frequent plucking of ear hair, can also predispose dogs to infections.

Adult Cats

In adult cats, ear infections are less common but often linked to ear mites, especially in outdoor or multi-pet households. Cats may also develop ear infections due to nasopharyngeal polyps, growths that can obstruct the ear canal, or secondary infections from bacteria or yeast.

Managing Ear Infections

Once an ear infection is diagnosed, treatment typically involves addressing both the infection and any underlying causes. 

Cleaning

Infected ears need regular cleaning to remove debris and exudate. Your veterinarian may perform the initial cleaning and recommend a cleaning solution suitable for your pet’s condition. Avoid using harsh cleaners or squeezing solution directly into sensitive, inflamed ears—cotton balls soaked in cleaner can be used for a gentler approach.

Medication

Treatment for ear infections generally includes topical medications such as antibiotics, antifungals, and corticosteroids. These reduce inflammation and pain while targeting the infection itself. Depending on the severity, your vet might also prescribe oral medications or recommend a course of NSAIDs or glucocorticoids to reduce inflammation. In many cases, your veterinarian may recommend a laboratory culture of the ear discharge to identify the specific bacteria and guide antibiotic choice.

Underlying Conditions

Since many ear infections are secondary to conditions like allergies, addressing the root cause is essential. This might involve dietary changes, allergy testing, immunotherapy, or managing a skin condition long-term.

Dos and Don’ts for Pet Owners

Here are some practical tips for managing your pet’s ear health:

Dos

• Pay attention to symptoms such as head shaking, scratching, and discharge.
• Finish all medications as prescribed by your vet, even if symptoms improve early.
• Consult your vet before using any over-the-counter products, cleaners, or home remedies.
• Monitor your pet's diet and environment, as allergies can exacerbate ear problems. 
• Consider using probiotics or other microbiome solutions to support healthy ears in pets prone to recurrent infections.
• Use maintenance products like MalAcetic or Burrow’s solution as directed by your vet to keep chronically infected ears dry and healthy.
• Dry your pet’s ears thoroughly after bathing, grooming, and swimming.

Don’ts

• Don’t use ear cleaners or medications without veterinary guidance, especially inside the ear canal.
• Don’t use cotton swabs or other tools inside your pet’s ear canal.
• Avoid plucking hair from the ear canal unless advised by your veterinarian.
• Don’t use leftover medications from a previous infection.

Summary

Ear infections in dogs and cats can cause significant discomfort, but with proper management and preventive care, many can be treated effectively. Regular veterinary visits, early recognition of symptoms, and a proactive approach to your pet’s overall health can help reduce the frequency and severity of these infections. Keep your pet’s ears clean and dry, and work closely with your vet to address any underlying health conditions.