Overview of Ear Infections in Dogs
Otitis externa, commonly referred to as an “ear infection”, is an ear condition characterized by inflammation of the dog’s external ear canal. It is particularly prevalent in dogs with long, floppy ears and is relatively uncommon in cats. Ear infections represent one of the top 10 reasons dogs present to veterinarians and may affect up to 20 percent of dogs.
Infections are caused by fungus, bacteria or parasites. Laboratory tests can help to determine the underlying cause of the infection. Ear mites can cause 5-10% of ear infections in dogs.
Several factors may predispose dogs to ear infections, including:
- Long floppy ears
- Abnormal ear conformation or anatomy
- Water in the ears (such as with frequent swimming or bathing)
- Hair in the ears (such as with poodle breeds)
- Foreign material in the ears
- Autoimmune disease
- Generalized skin disease
- Stenotic ear canals (such as with English bulldogs, shar-peis and chow-chows)
Ear infections can occur in dogs of any age breed or sex. Dogs predisposed to otitis externa include those with genetic predispositions to abnormal ear canals, such as the Chinese shar-pei s, chow chows, and English bulldogs; breeds with hair in the ears like poodles and terriers; dogs with pendulous pinnae such as the cocker spaniel, Brittany spaniels, basset hounds, beagles and Springer spaniels; or outside and working dogs that are exposed to water or foreign bodies. Infections are most common in humid environments or during the summer months.
What to Watch For
Common signs of an ear infection in dogs include:
- Scratching or rubbing the ears
- Head shaking
- An abnormal odor or discharge from the ear
- Pain when you manipulate the ear
- Redness and swelling of the external ear canal
- Hearing deficits
Dogs at risks include a dog that frequently swims, dogs with excessive ear care such as ear plugging or excessive cleaning and dogs with underlying allergies. Ear infections are more common in the summer months when swimming, increased humidity and seasonal allergies increase. Excessive cleaning with cleansers can keep the ear canal moist and skin susceptible to infection. Ear infections can affect any age, breed or sex of dogs. Generalized skin problems may suggest underlying allergies.
Diagnosis of Otitis Externa in Dogs
- 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 dogs may require additional diagnostic tests to determine the underlying cause of the abnormalities. Dogs with recurrent ear infections, those who respond poorly to treatment, dogs 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 scraping tests may be recommended to determine the presence of parasites or mites.
- Allergy tests to determine if your dog is allergic to things that may irritate the ears, as well as the skin.
Treatment of Otitis Externa in Dogs
Treatments for otitis externa may include the following:
- Cleaning the ear. This can be accomplished by placing solutions in your dog’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 dog’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.
Home Care and Prevention
- 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 dog’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 dog’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 dog’s ears checked by your veterinarian.
Information In-depth on Otitis Externa in Dogs
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 diseases, such as systemic or discoid lupus erythematosus or pemphigus
- Contact allergy
- Endocrine imbalance
- Food allergy
- Foreign bodies such as foxtail awns
- Ear diseases like cancer, hyperplasia or polyps
- Parasites like ear mites, which are responsible for 10 percent of otitis in dogs
- Sebaceous adenitis
- 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 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.