Otitis Interna and Media in Dogs
The ears are responsible for taking sound waves from the air and transporting them to the brain. These waves pass through the ear canal until they come in contact with the nerves that convert them into sound and allow for hearing. Head shaking
The ear canals are divided into three sections; the external, middle and internal parts. The external ear canal extends from the outside of the ear lobe to the eardrum. The middle ear begins with the eardrum and includes the bones and nerves of the ear. The inner ear is closest to the brain and contains the organs responsible for maintaining proper position.
If the inner ear is not functional, the animal feels dizzy and the brain is not able to determine if he/she is standing, turning, lying down, spinning. The most common abnormality associated with the middle and inner ear is inflammation, which is referred to as otitis media or otitis interna. Otitis is the Latin term for inflammation within the ear. Media and interna refer to the parts of the ear that are inflamed. Otitis externa refers to an external ear canal inflammation or infection.
Inflammation within the ear can have numerous causes including bacteria, fungi, yeast, parasites, foreign objects, trauma, polyps and cancer. Middle ear infections typically occur in association with external ear infections. Inner ear infections can then occur as a progression of a middle ear infection. For this reason, prompt diagnosis and treatment of external ear infections can significantly reduce the chance of a middle and/or inner ear infection.
Deafness is a possible permanent effect if otitis media/interna is not treated appropriately. Signs of middle and inner ear inflammation vary depending on which part of the ear is affected and the severity of the infection.
What to Watch For
Pawing, rubbing at the ear
Discharge from the external ear canal
Pain when the head is touched
Pain with the mouth is opened
Loss of hearing
Lack of appetite
Leaning to one side
Side to side involuntary continuous eye movement (nystagmus)
Otitis media and otitis interna are usually diagnosed based on results of a physical examination and thorough ear exam. Finding the exact cause of the ear inflammation requires more tests and may include:
Complete blood count (CBC) and biochemical profile to determine the overall health of the animal
Sedation or anesthesia for a thorough examination since the ear may be quite painful
Radiographs of the skull and base of the ear, although not usually helpful, to look for tumors or masses at the base of the ear
Culture and cytology of any discharge or fluid within the canal to determine the cause of the inflammation. Culture can detect bacterial causes and help determine the appropriate antibiotic treatment. Cytology can detect parasite, fungus, yeast and some cancers.
The goal of treatment for otitis media or otitis interna is to remove the cause of the inflammation and provide ventilation and drainage. Treatments vary depending on the cause of the inflammation and may include:
Initial flushing of the ear canal with warm saline (salt water solution)
If the eardrum is intact, a puncture through the eardrum to alleviate the pain and pressure as well as drain the middle and inner ear. This is painful and is done under anesthesia.
Flushing the middle ear after perforating the eardrum
Removal of any foreign object
Oral antibiotics for 3-6 weeks for bacterial, fungal and yeast infections
Ear medications must be used cautiously, if at all. Usually, flushing the ear and oral antibiotics resolves the infection. For parasitic causes of inflammation, ear medications may be necessary.
If the infection is resistant to treatment or if polyps or cancer is the cause of the inflammation, surgery may be necessary. Surgery is more likely if the inflammation has progressed to include the inner ear.
Home Care and Prevention
There is no home care for otitis media or otitis interna. See your veterinarian if your pet is showing signs of a middle or inner ear infection.
Prompt and thorough treatment of external ear infections can greatly reduce the risk of otitis media and otitis interna.
For dogs that hunt or spend time in wooded areas, frequent ear exams looking for foreign objects such as grass awns can help reduce the chance of foreign body induced otitis media/interna.