Otitis Externa in Dogs

Diagnostic Recommendations


Cytology of the ear canal involves collecting an ear swab. The material on the swab is then applied to a microscope slide and stained. Microscopic observation can help determine the type of infection or inflammation that is occurring so that more accurate medication can be recommended.

Ear Swab

The ear material can be removed on a swab. This is then applied to a microscope slide and stained. In addition debris from the ear is mixed with mineral oil to loosen and disperse mites from the material. Microscopic examination will reveal any organisms or disease.

Culture and Sensitivity

A culture and sensitivity test is performed at our reference laboratory. It involves trying to grow the bacteria in the laboratory so that tests can be done to determine which antibiotic medications will be most effective in controlling this bacteria. This test will take several days and the results will help us prevent reoccurrence of this problem.

Therapeutic Recommendations

Therapeutic Flushing

Because of its shape the ear canal tends to trap and retain glandular secretions (wax) debris from cells, foreign bodies, hair and moisture. This material build-up prevents medications from reaching the problem areas and may inactivate antibiotic medications. Therefore a flushing and cleaning of the ear canal prior to therapy is recommended. This procedure may require sedation if the ear canal is painful.

Sedation by Injection

IV injection of a rapidly acting anesthetic is usually all that is needed to perform a painless ear flush procedure. Rapid recovery is expected with minimal “hangover” effect.

Thyroid Hormone Assay

Low thyroid hormone is commonly associated with chronic ear disease. We recommend thyroid testing in all cases of reoccurring ear disease. It will require a simple blood test that can be taken now and sent to our reference laboratory.

Hypoallergenic Diet

Many ear diseases are caused or exacerbated by allergic disease. We recommend a hypoallergenic diet such as Prescription Diet® Canine d/d® for those pets with possible allergic ear disease. This food is composed of a limited number of highly digestible ingredients.

Essential fatty acid supplements

Essential fatty acid supplements play an important part in modulation of the inflammatory response and will help control the itching and inflammation associated with ear disease. These supplements are also helpful in managing the excessive wax production component of this disease.

Cautions Regarding Therapy of Ear Disease

Ear disease can be frustrating to treat and poor or incomplete response to therapy is common. If these medications are not effective, additional testing will be recommended such as culture and sensitivity. Thyroid testing as well as allergy testing may also be recommended. Surgical opening of the ear canal is sometimes necessary if improper drainage of ear secretions is a perpetuating factor in the ear disease process.

Home Care Instructions for Ear Conditions – Dry Ears

Keep the ear dry – no swimming – use a drying solution if the ears become wet or after bathing.

Epi-otic Ear Cleanser

This is a drying ear cleanser that creates an acid pH in the ear canal that is antibacterial and antifungal. Use this for maintenance twice weekly and after the ears become wet.


Apply to affected ears once daily- Contains gentamicin, mometasone and clotrimazole. Gentamicin is effective against gram negative and gram positive organisms. Mometasone is a topically acting steroid. Clotrmazole is an effective antifungal agent.

Baytril Otic®
Apply to affected ears twice daily- Contains enrofloxacin (Baytril) and silver sulfadiazine(SSD). Enrofloxacin is a broad spectrum antibiotic, SSD is a potent antifungal agent with antimicrobial and anti-inflammatory properties.

Apply to affected ears twice daily- Contains gentamicin, betamethasone and clotrimazole. This medication is used for refractory yeast infections, which are resistant to previous therapies.

Acarex contains 1% Ivermectin solution and is effective at killing ear mites. Apply the treatment to both ears. Repeat in two weeks.

Cortizone injection
Injection of corticosteroid is given to reduce the inflammation and pain in the ear canals to better allow topical medications to be given.

Panalog® is a good broad spectrum antibiotic/antifungal/antiinflammatory combination. Apply twice daily.

Statements to use if the infection is considered chronic.
Because of its shape, the ear canal tends to trap and retain glandular secretions (wax) debris from cells, foreign bodies, hair and moisture. Surgical opening of the ear canal is sometimes necessary to alleviate the structural causes of poor response to medical therapy.
The ear canals produce large amounts of wax and debris that may prevent the medications from working. Therefore, weekly ear flushes are necessary until this condition is managed. This ear irrigation may require sedation to be effective and non-painful to the patient.

Diagnostic Recommendations

Pre-operative blood screen
Any anesthetic procedure has risks. To help minimize those risks a blood test to determine the internal state of the organs is recommended. This blood test will determine if your pet is anemic, has any infections or internal organ disease such as kidney or liver dysfunction.

The heart has stresses placed on it during anesthesia that are different from those that are present in every day life. Because of this we recommend a pre-surgical Electro-Cardiogram (ECG) screen to determine if the heart is functioning normally at this time and to help modify the anesthetic regime if necessary to compensate for any abnormalities seen on the ECG.

IV Fluid Therapy
During anesthesia the blood pressure tends to drop which can be harmful to the internal organs especially the kidneys. IV fluid therapy during the procedure helps maintain normal blood pressure as well as offers easy access to the vein should an emergency occur.

Isoflurane Gas Anesthesia
Isoflurane gas is a relatively new gas anesthetic that has fewer side effects on the patient than other commonly used anesthetics. This gas does not require internal organ metabolism of it for the patient to “wake-up”. This gives us more accurate control of the depth and length of the anesthetic period. Thereby allowing for rapid recovery and minimal “hangover” effects.

Allergy Testing
Atopic dermatitis can be responsible for ear disease. This ear/skin reaction is due to allergies to inhaled pollens. A blood test is recommended to determine the actual pollens that your pet is allergic to. This testing process will be followed by the creation of a specific allergy injection protocol for your pet to alleviate the underlying cause to this disease.