OVERVIEW

Otitis externa, or inflammation of the external ear canal, is a common condition in dogs. It is characterized by inflammation of the soft tissue components of the external ear canal and is particularly prevalent in dogs with long, floppy ears. Otitis externa may affect 20 percent of dogs.
Several factors may predispose your pet to ear infections, including:

Abnormal ear conformation or anatomy
Water or hair in the ears
Allergies
Trauma
Tumors
Foreign material in the ears
Parasites
Autoimmune disease
Generalized skin disease

Infections are caused by fungus, bacteria or parasites. Laboratory tests can help to determine which of these is the cause in your pet. Dogs predisposed to otitis externa include those with genetic predispositions to abnormal ear canals, such as the Chinese shar-pei; breeds with hair in the ears like poodles and terriers; or outside and working dogs that are exposed to water or foreign bodies.

Scratching or rubbing the ears
Head shaking
An abnormal odor or discharge from the ear
Pain when you manipulate the ear

Veterinary care should include diagnostic tests to determine the underlying cause and help guide subsequent treatment recommendations. Tests may include:

Complete medical history and physical examination with special attention to the ears and skin

Cytology, which involves taking a sample of the ear discharge or any masses and examining it under a microscope

Some pets may require additional diagnostic tests to determine the underlying cause of the abnormalities. Pets with recurrent ear infections, those who respond poorly to treatment, pets with generalized skin abnormalities, or those with other health problems may need additional diagnostic tests. These may include:

Culture and sensitivity. This procedure involves taking a sample of the ear discharge and sending it to a laboratory to identify the specific bacteria present. The bacteria are exposed to multiple antibiotic samples to determine what will kill them most effectively.

Radiographs (X-rays) to determine the health of the ear canal and bone and to evaluate the extent of involvement

Complete blood count (CBC) and biochemical profile to check for factors that may contribute to the infection as well as to determine if a concurrent disease is present

Skin tests

Allergy tests to determine if your pet is allergic to things that may irritate the ears, as well as the skin

Treatments for otitis externa may include the following:

Cleaning the ear. This can be accomplished by placing solutions in your pet's ear at home or by having the ears cleaned by your veterinarian. Moderate to severe infections may require sedation and in-hospital flushing.

Topical therapy. It usually consists of an ear medication that you place in your pet’s ear once or twice daily. The specific medicine and directions will depend on the cause of the infection. It is extremely important to follow your veterinarian’s directions carefully.

Systemic therapy with glucocorticoids (steroids) to decrease pain and inflammation

Antibiotic therapy in cases of severe bacterial infection or ulceration

Antifungal therapy in cases of severe or recurrent yeast infections

Anti-allergy therapy

Optimal treatment requires a combination of home and professional veterinary care. Be sure to have your veterinarian or his/her staff show you how to place medication into your pet’s ears.

Do not use cotton swabs in the ear; these may push infection and/or discharge deeper into the ear canal. Clean the ears before applying medication.

Return to your veterinarian for follow-up examinations as suggested.

At home special care of your pet's ears can help to maintain healthy ears. Dry the ears after bathing or swimming and check ears for foreign matter.

Also, at the first sign of scratching, head shaking, pain, swelling, odor, or discharge, have your pet's ears checked by your veterinarian.

INFORMATION IN-DEPTH

Other medical problems can lead to symptoms similar to those encountered in otitis externa. It is important to exclude these conditions before establishing a definite diagnosis. Examples are:

Atopy. Fifty-five percent of dogs with itchy skin disease caused by an allergy have otitis externa.

Autoimmune disease, such as systemic or discoid lupus erythematosus or pemphigus

Contact allergy

Demodicosis

Endocrine imbalance

Food allergy

Foreign bodies such as foxtail awns

Ear disease like cancer, hyperplasia or polyps

Parasites like ear mites, which are responsible for 10 percent of otitis in dogs

Polyps

Sebaceous adenitis

Seborrhea

Trauma

Tumors. The following have been reported: squamous cell carcinoma (more common in cats than dogs), histiocytomas, sebaceous gland adenomas, adenocarcinomas, basal cell tumors, mast cell tumors, chondromas, chondrosarcomas, trichoepitheliomas, apocrine gland adenomas, fibromas, fibrosarcomas, and papillomas

Zinc-responsive dermatosis

VETERINARY CARE IN-DEPTH

DIAGNOSIS IN-DEPTH

 

Veterinary care should include diagnostic tests and subsequent treatment recommendations. Tests are needed to confirm the diagnosis of otitis externa and exclude other diseases that may cause similar symptoms. The following diagnostic tests are often recommended:

Complete medical history and physical examination to examine your pet’s external ears. Your veterinarian will pay close attention to the size of the ear canal, presence of pain, smell of ears, presence of hair or foreign material, masses or polyps, character of discharge/exudates, soundness of the ear drum, and general health. Your pet may need to be sedated.

Cytology to identify parasites, yeast organisms, bacteria and cellular components. This test will help to determine the cause of otitis externa and choose the proper treatment for your pet.

Culture and sensitivity tests in cases of recurrent infections, as there are some organisms that are often resistant to many antibiotics

Biopsy of growths to determine the presence of tumors

Radiography (X-rays) to evaluate the degree of the disease

Your veterinarian may suggest a referral to a dermatologist in difficult or recurrent cases or additional diagnostic tests to exclude or diagnose other conditions or to better understand the impact of otitis externa on your pet. These tests are selected on a case-by-case basis and may include:

A complete blood count (CBC) to evaluate your pet for other problems such as infections or inflammations

Serum biochemistry tests if there are other abnormal symptoms on the physical examination such as weight loss

Urinalysis to evaluate the kidneys and bladder

Thyroid level tests to determine the presence of hypothyroidism, which is the most common endocrine disorder that causes otitis externa in dogs

Adrenal function tests to rule out Cushing’s disease, which is hyperadrenocorticism secondary to excessive pituitary excretion of adrenocorticotropic hormone

Allergy tests to rule out allergic disease

Dietary trial to rule out allergic disease

Fungal cultures in the presence of severe or recurrent fungal infections

Skin scrapings to rule out mites such as Demodex

Treatment for otitis externa may include one or more of the following:

Treatment of the primary disease process, the underlying factors that predispose your pet to infection, and the specific infectious agent.

Initial management includes cleaning your pet’s ear. This can be accomplished by placing solutions in your pet’s ear at home or by having them cleaned by your veterinarian. Moderate to severe infections may require sedation and in-hospital flushing.

Topical therapy usually consists of ear medication that you place in your pet’s ear one to two times daily. The specific medicine will depend on the cause of the infection. It is extremely important to follow your veterinarian’s directions on getting the medicine in your pet’s ear. Improper medication and improper administration is a common cause for treatment failure.

Systemic therapy with glucocorticoids may be given to decrease pain and inflammation. These are hormones often used as inflammatory agents.

Antibiotic therapy may be indicted with severe bacterial infections or ulceration. Antibiotics may be chosen based on cytology and/or bacterial culture.

Antifungal therapy is indicated in cases of severe recurrent yeast infections.

Regular follow-up visits to your veterinarian are important to ensure that your pet’s condition does not worsen.

FOLLOW-UP

 

Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical. Follow-up for otitis externa often includes the following recommendations:

Administer prescribed medications as directed and be certain to contact your veterinarian if you are experiencing problems treating your pet.

Long term maintenance cleaning may be recommended in cases of long-standing infection. Cleaning procedure can be daily or weekly depending on the rate of wax and debris formation.

Administer any prescribed medications. NOTE: Inability to medicate your pet is a common reason for treatment failure.

Schedule regular veterinary visits to monitor your pet’s condition.

Periodic ear evaluations with cytology may be recommended.

Ear cultures may be useful in long-standing infections.

Of course, the precise follow-up depends on the severity of your pet’s disease, response to therapy and your veterinarian’s recommendations.