Cat Ear Infections

Lauren Jones, VMD
Written by:
Published: September 14, 2022
Cat Ear Infections

What Are Cat Ear Infections?

Otitis externa, commonly referred to as an ear infection, is an inflammation (swelling) of the outer ear canal. This inflammation may be acute (more recent) or chronic (long-standing). Otitis externa is a common condition in cats, less common in dogs, and it has a variety of causes.

The cat’s ear is divided into three main sections:

  • The outer ear

  • The middle ear

  • The inner ear

The eardrum separates the outer ear canal from the middle and inner ear, which houses very sensitive structures involved in hearing and balance. Chronic and severe outer ear infections can eventually become more serious infections of the middle or inner ear.

The outer ear includes the pinna, or the cartilaginous triangle part of the ear that is covered by skin, and the external ear canal. The pinna is shaped like a funnel to help sound waves get into the ear, down the ear canal, and into the parts of the ear that process sounds. Cats have very sensitive hearing, partly because of a larger canal as compared to humans. A deeper canal allows better processing of sound. However, a deeper ear canal may get more dirt and wax, contributing to infection and irritation.

The ear canal is lined by skin and has varying degrees of hair. The deep part of the ear canal is a dark, often moist environment that can be a breeding ground for yeast and bacteria.

Symptoms of Cat Ear Infections

Cats with ear infections may experience differences in severity and length of infection. Most often, cats will have these symptoms:

  • Head shaking

  • Scratching the ears

  • Head tilt

  • Ear discharge and odor

  • Swollen, red, and possibly ulcerated (having sores) pinna

  • Ear pain

Depending on the cause, ear infections may affect one or both ears. It is more common for both ears to be affected.

As the infection and inflammation progress to the inner and middle ears, cats may show signs of incoordination and vestibular issues. The vestibular system is involved in balance, motion, and orientation. Problems with the vestibular system are similar to vertigo in humans. They may also injure the pinna to the point of developing an ear hematoma (pool of blood).

Causes of Cat Ear Infections

Otitis externa has many causes. Predisposing factors, such as abnormal ear shape (like in Scottish fold cats) may increase the risk of ear infections. Cats with too much wax production, lots of ear hair, or abnormally small ear canals may also be predisposed.

Ear mites are common causes of ear infections in cats. Kittens and outdoor cats are more susceptible, because mites can spread between cats and dogs.

Allergies are also a common cause of ear inflammation and infection in cats. Cats may have an allergic reaction to food, the environment, or both. Cats typically have signs of skin disease with allergies and, because the ear canal is lined with skin, the ears can also be affected.

Bacteria and yeast are typically secondary and opportunistic infections. This means the primary problem is not the yeast or bacteria, but these pathogens take advantage of the weak and damaged ear canal in order to replicate, thereby causing additional disease.

Healthy ear canals can fight off and defend against bacterial and yeast overgrowth, but that ability is lost when it becomes diseased. The secondary infections are some of the most common types of ear infections.

The other causes of ear inflammation, and things likely to create secondary infections include:

  • Foreign bodies (grass awns or hair)

  • Polyps

  • Cancer

  • Disorders of the skin

  • Endocrine disorders (hypothyroidism, Cushing’s disease)

  • Immune-mediated disorders

  • Sebaceous gland disorders

  • Aggressive ear cleaning

  • Inappropriate treatments or medications not intended for the ear, such as hydrogen peroxide or alcohol can cause inflammation. Even some medications designed for use in the ear may cause problems if not prescribed by a vet, so it’s always important to check with your vet before using any medication on your cat. 

How Veterinarians Diagnose Cat Ear Infections

Veterinarians will suspect an ear infection based on a cat’s ear exam and the clinical signs. The ear canal and eardrum are checked for signs of inflammation, debris, masses, or other abnormalities. In more severe cases, the eardrum can rupture, which may change the treatments.

Veterinarians can diagnose ear inflammation and debris based on a physical exam alone, but more tests may be needed to confirm the presence of bacterial, fungal, or parasitic infections.

These include:

  • Cytology is the gold standard to diagnose ear infections. A swab is inserted into the affected ear to collect cells, debris, and discharge. These cells are then examined under a microscope for the presence of mites, bacteria, yeast, or inflammatory abnormal cells.

  • Culture of the affected ears involves inserting a sterile swab into the affected ear to obtain a sample of bacteria. These bacteria are then grown in a laboratory setting and tested against other different strains of bacteria to see which type your pet is most sensitive to.

  • Imaging and other tests may be necessary for chronic or cases that don’t respond to treatment.

Treatment of Cat Ear Infections

Treatment is aimed at the underlying cause of the infection, as well as treating any secondary infections. Cold laser therapy is often used, along with medications to help treat pain and decrease inflammation.

  • Ear mites: Topical antiparasitic medications, like Revolution, are often used to treat ear mites. Some topical antiparasitic drugs may also be placed directly into the ear canal as well.

  • Allergies: There are many ways to treat allergies, but the first step is to figure out if it is an environmental allergy or a food allergy. Diet trials may be used as well as specialized testing to find potential allergens. The goal with allergy testing is to produce an allergy vaccine with an allergen profile specific to the pet patient.

  • Bacterial and yeast infections: These are typically secondary to an underlying cause, but they still require treatment. Most often, medications containing an antibiotic, an antifungal, and an anti-inflammatory all in one are put into the affected ear canal. Some otic (ear) preparations are intended to stay in the ear canal for 1 to 2 weeks. Others may need to be administered daily, or twice daily by pet parents.

Ear cleaning is an important part of treating otitis externa. Debris left in the ear canal can continue the infection and make treatment more difficult.

To clean the ear, fill the canal with the cleaner and gently massage, wiping out what you can feel in the vertical part of the ear (feels like an ice cream cone). You could do damage if you try to go deeper.

For appropriate and accurate treatment, make sure to talk to your veterinarian about the correct way to give medication and clean your cat’s ears. Many veterinarians recommend Epi-otic for cleaning, but always check with your vet before starting any medications or supplements. 

In more severe cases, oral anti-inflammatory drugs (steroids or NSAIDS) may be needed to decrease inflammation and treat pain. Oral antibiotics and antifungals may also be needed in severe, chronic, or recurrent cases of otitis.

Surgery may be needed for tumors, foreign bodies, or polyps in the ear canal.

Home Remedies for Cat Ear Infections

Ear cleaning at home can be an important part of helping your cat’s ears stay healthy and finding problems early.

While there are many over-the-counter products that claim to treat ear issues, the ear is a very sensitive organ. Many products are toxic to the ear and may result in pain, hearing loss, ulcerations (breaks in the skin), and even neurologic signs. It is always best to have your veterinarian diagnose and treat any ear issues.

Recovery and Management of Cat Ear Infections

Cats usually start feeling better within a few days of treatment. Once they seem to recover, it could be tempting to stop treatment, or cancel follow-up appointments. However, all medications should be used for the full treatment length (usually 7 to 14 days) and a recheck exam with cytology should be scheduled. Common causes of treatment failure include treatment that’s not long enough and inadequate therapy. It is important to learn how to clean and medicate your cat’s ears to ensure the product reaches the deep part of the ear canal.

The recheck cytology and veterinary exam is important because it may show one or more of the following things:

  1. The ear infection is better, but not fully resolved (even if the pet is feeling completely fine).

  2. The ear infection is resolved, and treatment can be stopped.

  3. The ear infection has changed and now requires a different course of treatment.

Some cats may have recurring ear infections, especially if they have abnormal ear canal anatomy or chronic predisposing issues, like allergies. Other issues, such as foreign material or ear mites, are more readily cured and do not recur.

In general, cats with ear infections have a good prognosis. Early intervention, fully completing any medications, and treating underlying factors are the keys to success.

References

  1. Veterinary Manual. Ear Structure and Function in Cats.

  2. Veterinary Information Network. Otitis Externa, General Information (Feline).

Featured Image: iStock.com/simonkr


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