How common are ear infections in dogs?
Infection of the outer ear, or otitis externa, indicates chronic inflammation of the external ear canal. This type of infection, caused by bacteria or yeast, is one of the most common types of infections seen in dogs. Some breeds seem more prone to ear infections, but they may occur in any breed.
What are the symptoms of an ear infection?
A dog with an ear infection is very uncomfortable. The ear canals are sensitive and the dog will shake his/her head trying to get the debris and fluid out. Many dogs will also commonly scratch at the ears. As a result, the ears often become red and inflamed and develop an offensive odor. A black or yellowish discharge also commonly occurs. Some dogs do not show any signs of infection. Regardless, all dogs should be treated because thickening, scarring and resistant infections can develop in untreated ears.
Don't these symptoms usually suggest ear mites?
Ear mite infections generally occur most commonly in puppies. Ear mites in adult dogs occur most frequently after a puppy carrying mites is introduced into the household.
Can I pick up my dog's medication without an appointment?
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. In some cases, the ear infection may be caused by a foreign body, such as a foxtail or tumor in the ear canal. In these cases, 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.
dditionally, it is important to note that many ear infections have an underlying cause. 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 an ear 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. 
The next step is to perform an ear cytology, or the examination of a sample of the material from the ear canal, 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. 
An important part of evaluation is the identification of underlying disease. Many dogs with chronic ear infections have allergy problems (food, pollens, fleas) or low thyroid function (hypothyroidism). If an underlying cause 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). 
What is the prognosis?
Nearly all ear infections that are properly diagnosed and treated can be cured. However, if an underlying cause remains unidentified and untreated, the outcome will be less favorable.
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:
  • Gently pull the earflap straight up and hold it with one hand.
  • Apply a 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 medication to run down to the turn between the vertical and horizontal canal.
  • Put one or two fingers behind the earflap at the base. Place your thumb on the opposite side of the base.
  • Massage the ear canal between your finger and thumb. A squishing sound tells you that the medication has gone into the horizontal canal.
  • 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. A technician will review how to medicate and clean the ears during your appointment. A video tutorial is also available.