Ear Care
By Dr. Karen Thomas

They stand, droop, or fold. They face forward, backward, or both. “They” are ears. In dogs the hanging ear is genetically dominant over the upright so a lab/shepherd cross should always have floppy ears and ears of a chow/shepherd should always stand. In some dogs the left ear and right don’t even match. In cats the ears of different breeds vary mainly in size and placement on the head except for the Scottish fold whose ears bend forward and the American curl whose ears fold backwards.

The ear flap, which is call a pinna, is susceptible to injury, which has led to the practice of cutting or cropping part of the ear, especially in dog breeds which were once used for fighting or protection. Today many people believe this practice should be outlawed as it may be both painful and dangerous for the pet. The tip of the pinna on upright eared dogs or the fold on ears which flop are often attacked by flies in the summer . There are a number of sprays and creams which can be used to repel flies. On white cats the tips of the ears may be the site of sun induced cancer and they should be monitored if the cat is outside all the time. Another sort of injury which can occur to the pinna is a hematoma. It is not certain whether this is a broken blood vessel or fractured cartilage, but it causes a painful swollen ear flap which may need to be treated surgically.

The ear canal of the dog and cat is a long funnel shaped tube which has a right angle in the middle so that the first part of the canal runs downhill parallel to the head and then the lower part angles inward to the ear drum. This unfortunately causes wax and dirt to stay deep in canal especially when the exterior opening is closed by a hanging ear flap. Therefore ear infections are common in dogs. Any kind of moisture in the ear can cause infection, but the most common factor contributing to ear infection is skin allergies caused by reaction to fleas, food, or inhalants. The lining of the canal becomes swollen and oozes excess serum and wax, a perfect medium for the growth of bacteria and yeast. If the affected ears are not kept clean and dry and free of infection there can be permanent changes in the cartilage and lining which can only be corrected surgically. In some cases the only way to free the dog of pain and infection is to completely remove the entire ear canal.

Another common cause of ear infection is the earmite, a tiny bug about the size of the dot at the end of this sentence. Mites can cause severe itching and inflammation or they may be present with no reaction at all. They can infect cats, dogs, rabbits, and ferrets, but not people, and they are very contagious. Since infection can be inapparent, when mites are diagnosed all “in contact” animals must be treated to eliminate the infection. In rare instances, mites can be present on the head and body as well as in the ears, and another kind of mite, called demodex, can infect the ear. There are several different medications which may be used to kill the mites, and anti-bacterial and anti-inflammatory medications may also be needed. A veterinarian should be consulted to confirm the diagnosis and provide the most appropriate medication.

The ear canal can also be the site of tumors or inflammatory polyps. These may be seen as a mass in the canal, or bleeding from the canal, or just as intractable infection when the growth is deep within the canal where it cannot be seen. In cats, polyps may also grow down the eustachian tube into the throat where they can interfere with breathing. Polyps are often due to long standing inflammation or infection and may become tumors if the cause is not eliminated. But the growth must be removed to treat the cause.

The inner ear is the center of balance, and inflammation or infection of the inner ear can cause loss of balance or head tilt. Ear infection may extend from the outer ear canal, or there may be no evidence of infection in the visible ear canal if the infection enters the middle ear through the eustachian tube from the throat or by way of the blood stream.

Middle and inner ear infections may respond to oral antibiotics or surgical treatment may be necessary to drain the fluid and pus from the bulla which is the echo chamber attached to the inner ear. Special x-rays taken under anesthesia may be necessary to diagnose the condition and determine if surgery is indicated. There are many cases of vestibular syndrome in the older dog or cat which have no infection present and which improve with time. The loss of balance may be so severe that the affected animal is unable to stand at all and simply rolls on the floor.