A Guide to Canine Ear Infections

Ear infections are one of the most common health problems dogs face. Here's what you should know:

What is an ear infection?

Infection of the outer ear, or otitis externa, indicates chronic inflammation of the external ear canal. This type of infection is often caused by bacteria or yeast. Infection of the middle or inner ear can also occur.

What are the symptoms?

Ear infections are typically very uncomfortable, though some dogs may not show any outward signs of a problem. Regardless, it is important that all infections are treated as thickening, scarring and resistance can develop.

Signs of an ear infection include:

  • Head shaking or tilting
  • Scratching at the ears
  • Redness and inflammation
  • Black or yellow discharge
  • Offensive odor

Does my dog need an exam?

Yes.

The primary reason for this is that there are several kinds of bacteria and at least one type of fungus that can cause an ear infection. Without knowing the kind of infection present, we cannot determine the best drug to treat it. If the infection is caused by a foreign body, such as a foxtail or tumor in the ear canal, treatment with medication alone will not resolve the problem.

The dog must also be examined to be sure that the eardrum is intact. Middle ear or inner ear infections can result if the ear drum is ruptured. This determination is made by the veterinarian and must be done in the hospital.

Additionally, it is important to note that many ear infections have an underlying cause, like allergies or hypothyroidism. Unless the underlying cause is also treated, the infections will become recurrent. The only way to know if an infection has been resolved completely is by looking in the ear and performing a cytology (cell study) to look for persistent organisms.

How do you determine which drug to use for treatment?

First, the ear is examined with an otoscope, which provides magnification and light and allows us to get a good look into the canal. From here, we can determine whether the eardrum is intact or if there is any foreign material in the canal. When a dog is in extreme pain, the exam should be done with sedation or under anesthesia. Some dogs also have such a heavy buildup of debris that sedation is needed to clean the canal and examine it completely.

An ear cytology, or the examination of a sample of the material from the ear canal, is used to determine which organisms are causing the infection. Study of the material under the microscope is very important in helping the veterinarian choose the right medication to treat the ear.

How are ear infections treated?

The results of the otoscopic examination and ear cytology tell us what to do. Sometimes the cytology reveals the presence of more than one type of infection (i.e., bacterial and fungal or two different kinds of bacteria); this situation usually requires the use of multiple medications or a broad-spectrum medication. In some cases, we will want to culture the debris based on the cytology results.

If a foreign body or tick is lodged in the ear canal, the dog will be sedated for removal.

If an underlying cause of infection is found, it must be diagnosed and treated. If treatment of the underlying disease is not possible, the dog is less likely to have a favorable response to treatment. The dog may also respond temporarily before relapse of the infection occurs (usually when the medication is discontinued).

Why is a recheck exam so important?

A recheck exam will be needed before the treatment process is completed. This exam is very important because the ears may need to be treated longer. While the dog's symptoms may have resolved because he/she feels so much better, an infection may still be present. It is impossible to determine whether the infection has cleared without rechecking the ears.

For chronic infections, routine care at home is key to keeping the problem under control.

How do I treat my dog at home?

It is important to get your dog's 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, while the horizontal canal lies deeper in the ear and terminates at the eardrum.

The ear canal may be medicated by following these steps:

  1. Gently pull the earflap straight up and hold it with one hand.
  2. Apply a small amount of medication into the vertical part of the ear canal while continuing to keep the earflap elevated.
  3. Hold this position long enough for the medication to run down to the turn between the vertical and horizontal canal.
  4. Put one or two fingers behind the earflap at the base.
  5. Place your thumb on the opposite side of the base.
  6. Massage the ear canal between your finger and thumb.
  7. A squishing sound tells you that the medication has gone into the horizontal canal.
  8. Release the earflap and let your dog shake his/her head.

If the medication contains a wax solvent, debris will be dissolved so it can be shaken out. It is also important to clean your dog's ears regularly. Directions for cleaning the ears are the same as the medication instructions above, except that the ear cleaning solution will need to be wiped out of the canal. 

This blog post originally appeared on The Drake Center.

 

 

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