Otitis Externa in Small Mammals

Ear infection, also referred to as otitis externa, is a condition characterized by inflammation of the soft tissue components of the external ear canal. This type of infection is not common in small mammals but does affect a significant number of ferrets and rabbits.

Several factors may predispose your pet to ear infections, including abnormal ear conformation (lop-ears), water or hair in the ears, allergies, trauma, tumors, foreign material in the ears, parasites or other generalized skin diseases.

Infection of the ears may be due to fungus, bacteria or parasites. Laboratory tests will help determine which of these is the cause in your pet. In ferrets and rabbits, the most common cause of ear infections is ear mites.

What to Watch For

• Scratching or rubbing the ears
• Head shaking
• An abnormal odor or discharge from the ear
• Pain when you manipulate the ear

Diagnosis

Diagnostic tests are needed to recognize otitis externa and exclude other diseases. Tests may include:

• Complete medical history and physical examination (with special attention to the ears and skin)
• Cytology (which involves taking a sample of the ear discharge or any masses and examining it under a microscope)

Some pets may require additional diagnostic tests to determine the underlying cause of the abnormalities. Pets with recurrent ear infections, those who respond poorly to treatment, pets with generalized skin abnormalities, or those with other health problems may need additional diagnostic tests.

Tests may include:

• Culture and sensitivity. Used for bacterial infections, this procedure involves taking a sample of the ear discharge and sending it to a laboratory to identify the specific bacteria present. The bacteria are exposed to multiple antibiotic samples to determine what will kill them most effectively.
• Radiographs. X-rays may be used to determine the health of the ear canal and bone and may be used to evaluate the extent of involvement.
• Blood tests. Complete blood count (CBC) and biochemical profile may be completed to check for factors that may contribute to the infection as well as determine if a concurrent disease is present.

Treatment

• Clean the ear. Initial treatment of an ear infection includes cleaning the ear. This can be accomplished by solutions you place in your pet's ear at home or by having the ears cleaned by your veterinarian. Moderate to severe infections may require sedation and in-hospital flushing.
• Topical medication. After a thorough cleaning, topical therapy is usually prescribed. This medication is placed in your pet's ear once or twice daily, depending on the cause of the infection. It is extremely important to follow your veterinarian's directions carefully.
• Injectable medication. For severe ear mite infestations, injectable medication, such as ivermectin, may be used. Antibiotic therapy may be indicated in cases of severe bacterial infection or ulceration. Antifungal therapy is indicated only in cases of severe or recurrent yeast infections.

Home Care and Prevention

Be sure to have your veterinarian show you how to place medication into your pet's ears. Make sure the ears are clean before applying medication, but don't use cotton swabs in the ear; these may push infection and/or discharge deeper into the ear canal.

Have your pet's ears checked at the first sign of scratching, head shaking, pain, swelling, odor or discharge.