Ettinger & Feldman — Textbook of Veterinary Internal Medicine
Client Information Sheet
Sandra R. Merchant
|What is otitis externa?Otitis externa is an inflammation or infection of the outer (external) ear canal. Many factors can cause or contribute to the development of otitis externa. Parasites (ear mites, ticks), foreign bodies (grass awns, dried medication, dried wax, displaced hairs), allergic disease (canine atopic dermatitis, food allergy), and diseases causing abnormal skin renewal time (keratinization disorders) have all been implicated as factors that directly causes otitis externa.
Factors that may predispose your pet to develop otitis externa include ear structure (long floppy ears, heavily haired ears, long narrow ear canals), errors in treating or cleaning ears (aggressive use of Q-Tips deep in the ear canal), and diseases that obstruct the ear canal (growths, swelling of the ear canal tissue). Factors that usually cannot cause otitis externa by themselves but can be a significant problem in need of treatment are bacterial and yeast ear infections. Sometimes pets with chronic otitis externa have problems beyond the ear drum (middle ear—otitis media), and these problems also need to be aggressively treated.
Many factors may come together in development of your pet’s ear problem. Recognition and subsequent treatment of all factors are the keys to successful clinical management of the otitis externa.
What are the symptoms of atopic dermatitis?
Atopic animals usually rub, lick, chew, bite, or scratch at their feet, muzzle, ears, armpits, or groin, causing hair loss and reddening and thickening of the skin. In some cases, several offending substances can “add” together to cause an animal to itch where each individual substance alone would not be enough to cause an itching sensation. These substances include not only airborne allergens (e.g., pollens) but allergens in food and from parasites (e.g., fleas) as well. Itching can also be exaggerated by bacterial or yeast infections of the skin. Sometimes, eliminating some but not all of the problems, a pet’s itchiness may go away. Therefore it is important to treat any other problems that could be making your pet itch while dealing with allergy.
What tests are needed?
A variety of tests may need to be performed. These may include culture or microscopic examination of the discharge from your pet’s ear. In addition, blood testing or skin testing for allergy may be needed. A dietary change may be recommended to determine of a food allergy is the cause of your pet’s ear disease. X-rays of the skull can aid in diagnosing middle ear problems.
What treatment is needed?
One or more in-hospital ear cleaning procedures may need to be performed on your pet. This may be as simple as an ear cleaning requiring just a few minutes with no or minimal sedation to more involved ear cleaning requiring more time and general anesthesia.
Attaining the goal of complete resolution of your pet’s ear disease depends heavily on your ability to clean and medicate your pet’s ears, follow through with therapy based on the results of the various tests, and faithfully return your pet for serial reevaluations at your veterinarian’s clinic.
Recurrent otitis externa not managed properly can cause chronic irreversible changes in the ear canal, most notably a narrowing of the ear canal diameter. This narrowing does not allow medication or cleaning solutions into the affected area. Further narrowing will not allow the normal ear wax secretions to exit the ear canal. Even though your pet’s ear may seem to be improved (less discharge, less smell, less discomfort), the ear disease may not be completely resolved and premature discontinuation of therapy can be detrimental to the chances for final resolution of the ear problem.
Sometimes, the underlying problem cannot be found or corrected. In these cases, a maintenance cleaning and medicating protocol may need to be formulated for your pet. If this protocol is followed, many ear problems can be controlled with minimal time and effort on your part and minimal discomfort for your pet.
Appropriate cleaning is a vital part of the overall program to appropriately address ear disease. The ear canal should be thoroughly cleaned of all debris before any medication is instilled in the canal. Your pet may object to having its ears cleaned initially, but better acceptance usually occurs with time. If your pet’s ear canal is red and uncomfortable at the beginning of treatment, gentle but thorough cleaning will help. After filling the ear canal with the ear cleaning solution, massage of the canal will help loosen the debris and discharge. The debris can then be massaged up from the base of skull (where the ear meets the head) to a cotton ball that is seated firmly in the opening of the canal. This procedure should be repeated until no more debris is recovered on the cotton ball. Medication is then placed in the canal and massaged down to the base of the ear. Q-Tips should never be used to clean the ear, except on the very outer ear folds. The key to successful cleaning is being consistent and thorough.
Reevaluations at the clinic are also a vital part of successful clinical management. Your pet’s ears may appear normal to you but may need continued medication and cleaning for complete resolution of the inflammation or infection. In dogs with chronic otitis externa, a maintenance cleaning or medicating protocol may need to be formulated based on the information obtained from the reevaluation visits.
If the ear disease has progressed beyond the outer ear canals, past the eardrum into the middle ear cavity, aggressive use of topical as well as oral medication may be needed. In addition, surgery to access the middle ear area for cleaning and identification of any infection may be necessary.