Otitis externa is a chronic inflammation of a dog external ear canal. Otitis media, meanwhile, is an inflammation of the dog's middle ear. Both of these terms are used to describe clinical symptoms and are not diseases in themselves.
Otitis externa often results when a change in the normal environment of the ear canal causes the glands lining the canal to enlarge and produce excessive wax. Gradually, the outer skin (epidermis) and the inner skin (dermis) produce excessive fibrous tissue (fibrosis) and the canal becomes narrowed. It is normally a secondary symptom of another underlying disease, such as an infection. Otitis externa causes pain, itching, and redness, and when the condition is chronic, it often results in a ruptured ear drum (tympanum) and otitis media.
Otitis media typically occurs as an extension of otitis externa, causing a ruptured membrane (tympanum) that separates the external ear and the middle ear. Otitis externa and otitis media affect dogs and cats of any age and breed, but long-eared dogs, such as spaniels and retrievers, and dogs with hairy external canals, such as terriers and poodles, are more susceptible.
The two conditions described in this medical article affect both dogs and cats. If you would like to learn more about how they affect cats, please visit this page in the PetMD health library.
The most common symptoms of otitis externa and otitis media are pain, head shaking, scratching at the external ear flaps, and bad odor. In a physical examination by a veterinarian, a dog with the condition may exhibit redness and swelling of the external ear canal, scaling skin or obstruction of the ear canal. Signs such as tilting the head, anorexia, uncoordination, and occasional vomiting may indicate the development of otitis media, or otitis interna, if the infection and inflammation spreads to the inner ear.
Otitis externa and otitis media can be caused by a variety of things. The primary causes are parasites, food allergies, drug reactions, foreign bodies (e.g., plant awns), accumulation of hair, dead skin buildup (keratinization), and autoimmune diseases.
Other factors that may contribute to the onset of the inflammatory conditions include bacterial infections, mixed infections caused by bacteria and fungal species, and progressive changes in the environment of the outer ear canal. Excessive moisture caused by swimming, or overzealous, abrasive, and improper ear cleaning may also lead to otitis externa and otitis media.
These two conditions can be diagnosed in several ways. For instance, X-rays may be used to diagnose otitis media; an magnetic resonance imaging (MRI) may also be used to identify an accumulation of fluid or soft tissue growth in the middle ear.
Other ways of diagnosing these conditions include skin scrapings from the dog's ear flaps to test for parasites, and skin biopsies to check for autoimmune diseases. However, the single most important tool for diagnosing otitis externa and otitis media is a microscopic examination of the ear discharge (aural exudate).
Treatment for otitis externa and otitis media usually involves outpatient care, unless the inflammation or infection has moved into the inner ear. In most cases of otitis externa, a topical therapy following a complete cleansing of the external ear is an effective resolution to the problem.
The topical therapy may consist of antibacterial, corticosteroid, anti-yeast, and antiseptic drops. In severe cases of otitis externa and otitis media -- where the presence of infectious organisms has been confirmed -- oral antibiotics and antifungals may be prescribed. Corticosteroids may also be used to reduce the animal's pain and swelling.
Follow-up treatments for otitis externa and otitis media involve repeat examinations of the ear discharge and control of any underlying diseases. You may be asked to routinely cleanse the dog's ear to prevent a recurrence. With the proper therapy, most cases of otitis externa will resolve within three to four weeks, whereas otitis media takes a considerably longer amount of time to treat it, and up up to six weeks to be resolved.
Inflammation of the external parts of the ear
A medical condition in which the ear becomes inflamed
Inflammation of the inner part of the ear
Inflammation of the middle parts of the ear
A type of fungus that produces buds
A bundle of fibers that are used in the process of sending impulses through the body
The outside layer of the skin
Any drug that kills organisms in an animal's tissue or prevents the growth of more.
Referring to the ear.
Loss of hearing in whole or in part.
The skin; also referred to as the corium
Used to refer to any drug or medical substance that has the ability to slow down or stop the growth of bacteria and other such organisms.