Symptoms

A dog with an ear infection is uncomfortable because its ear canals are very sensitive. It shakes its head and/or scratches its ears, trying to get rid of the foreign debris and fluid. The ears often become red and inflamed, develop an offensive odor, and leak a black or yellowish discharge.

Ear mites can cause these symptoms as well, but are most common in puppies. Sometimes mites will create an environment within the ear canal that leads to secondary bacterial and fungal infections. By the time the dog is brought to the veterinarian, the mites may be gone but a significant ear infection remains.

Diagnosis

An office visit is required to diagnose the cause of your dog's ear infection and treat it appropriately. There are several kinds of bacteria and at least one type of fungus that cause ear infections. In other cases, infections are caused by foreign bodies or tumors in the ear canal. Treatment with medication alone will not resolve these problems. Also, your vet must verify that your dog's eardrum is still intact, because administration of certain medications to a ruptured eardrum can result in hearing loss.

First, your vet will examine your dog's ears with an otoscope, which provides magnification and light for a better view of the ear canal. This allows us to determine the state of the eardrum and locate any foreign material. Some dogs have such a heavy buildup of debris, or are in so much pain, that sedation is needed to cleanse the canal and examine it thoroughly.

Next, we will perform a cytology. This involves taking a sample of the discharge from your dog's ear canal and examining it on a microscopic slide.

Treatment

When we've determined which organism is causing the infection, we know which medication to prescribe. Sometimes cytology reveals the presence of more than one type of infection (i.e., a bacterium and a fungus or two kinds of bacteria), requiring the use of multiple medications or a broad-spectrum medication. If a foreign body or tick is found, your dog may need to be sedated so it can be safely removed.

It is also important to determine if there is an underlying disease. Many dogs with chronic or recurrent ear infections have allergy problems or low thyroid function (hypothyroidism). If an underlying disease is found, it must be diagnosed and treated. Otherwise, the dog is less likely to have a favorable response to treatment - or might respond temporarily and relapse at a later time (usually when treatment is discontinued).

Prognosis

Nearly all ear infections that are properly diagnosed and treated can be cured. However, if an underlying disease remains unidentified and untreated, the outcome will be less favorable. Progress checks may be needed to verify total and successful treatment.

Complications

Dogs with ear infections are miserable. Their ears are a source of constant pain resulting in head shaking and scratching. This activity can cause broken blood vessels in the earflap, which necessitates reparative surgery. Chronic ear infections can also penetrate the eardrum and result in an internal ear infection.

Closing of the ear canal may occur. While there are medications that can shrink the swollen tissues and open the canal, some cases will eventually require surgery.

Ear Surgery

The surgery for a closed ear canal is called lateral ear resection. Its purposes are to remove the vertical part of the ear canal and swollen tissue from the horizontal canal. Removing the vertical canal is usually successful, but removal of large amounts of tissue from the horizontal canal is more difficult. In some cases, the ear canal is surgically obliterated. This solves the canal problem, but it leaves your dog deaf on one side.

Medicating

It is important to get ear medication into the horizontal part of the ear canal. Be aware that the dog's external ear canal is "L" shaped. The vertical canal connects with the outside of the ear; the horizontal canal lies deeper in the ear and terminates at the eardrum. The ear canal may be cleaned and medicated by following these steps:

1. Gently pull the earflap straight up and hold it with one hand.

2. Apply a large amount of cleanser - or small amount of medication - into the vertical part of the ear canal while continuing to keep the earflap elevated. Hold this position long enough for the cleanser or medication to run down to the turn between the vertical and horizontal canal.

3. Put one finger in front of and at the base of the earflap, and put your thumb behind and at the base.

4. Massage the ear canal between your finger and thumb. A squishing sound tells you that the medication is going into the horizontal canal.

5. Release the ear and let your dog shake its head. If the medication contains a wax solvent, debris will be dissolved so it can be shaken out.

6. If another medication is to be used, apply it in the same manner.

When all medications have been applied, clean the outer part of the ear canal and the inside of the earflap with a cotton ball soaked in a small amount of ear cleanser. (Do not use cotton-tipped applicators as they tend to push debris back into the vertical ear canal.)