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Otitis Externa (Ear Infection/Infestation and Inflammation)
Understanding Your Pet's Medical Diagnosis
What is otitis externa?
"Otitis externa" is defined as inflammation of the outer ear canal. The outer ear is that part of the ear external to the eardrum. It includes the part of the ear that can be seen. Frequently, otitis externa is accompanied by otitis media. "Otitis media" is defined as inflammation of the middle ear (which starts at the eardrum). Neither term is a true disease; rather, they are descriptions of disease and its location.
What causes otitis externa?
Otitis externa is caused by a variety of disorders. All dogs and cats can be affected with otitis externa, but certain breeds of dogs are more likely to be affected. Dogs with floppy or pendulous ears, especially spaniels and retrievers, and dogs with hairy ears, such as terriers and poodles, are more prone to inflammation of the outer ear. Excessive moisture, due to swimming or to frequent cleanings with improper solutions, can lead to infections that cause inflammation. Other causes include:
What are the signs of otitis externa?
Otitis externa is often a sign of an underlying disease. Infection results in inflammation and the production of pus. Inflammation causes pain and redness. The pet may shake its head and scratch its ears. The animal may hold one ear in an unusual position. The animal may tilt its head or have uncoordinated movements. A foul odor may be noticed from the ear. Poor appetite and vomiting may occur.
How is otitis externa diagnosed?
Otitis externa is diagnosed upon history and physical examination. The veterinarian will examine the ear using an otoscope, looking for signs of inflammation or infection. If present, ear mites will be detected by the otoscopic examination or by evaluation of the earwax or discharge under the microscope. Microscopic examination of ear drainage is the most important diagnostic tool after the examination of the ear canal. Other diagnostic procedures include complete blood counts (CBCs), blood chemistries, and urinalysis that may indicate the presence of an underlying disease. Radiographs (X-rays) may assist in determining the extent of otitis media. Skin scrapings may reveal mange mites. Skin biopsy (removal and examination of tissue from the ear canal) may reveal immune-mediated disease or cancer.
How is otitis externa treated?
The treatment for otitis externa will be based upon the underlying disease and the severity of the disease. If signs such as poor coordination, poor appetite, or vomiting are severe, hospitalization may be necessary for administration of fluids; but most pets with otitis externa can be treated at home. Generally, the ear will need to be cleaned. The veterinarian will show you the proper method for cleaning ears, as the eardrum can be ruptured easily. Commercial ear cleansers are effective and may be advised, but many should not be used if the eardrum is ruptured. Parasites (such as ear mites) can be treated with specific medications. Antibiotics will be prescribed for bacterial infections. Antifungal medication is prescribed if fungal or yeast infection is present. Anti-inflammatory medications (such as steroids) may be used to reduce swelling and pain. Surgery is indicated when the ear canal is severely obstructed or when cancer or a polyp is diagnosed. Routine ear cleaning is necessary to maintain a healthy ear.
What is the prognosis for animals with otitis externa?
The prognosis (outcome) for animals with otitis externa is variable. With proper therapy, most cases of otitis externa should resolve in three-to-four weeks. Unfortunately, many pets with otitis externa will have recurrences. Chronic otitis externa is difficult to control. Uncontrolled otitis externa can lead to otitis media, deafness, problems of the nervous system, facial nerve paralysis, and more serious inflammations of surrounding tissues.
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