Pet Care : dogs
Ear Infections in Dogs and Cats
We'll start with cats because ear infections are not as common in cats as they are in dogs, and the majority of ear infections are caused by one thing: ear mites! Ear mites are small bugs essentially. They are contagious between cats. Once they get started in the ear canal, the irritation is relentless. Ear mites crawl around in the ear, causing intense itching. Many cats with ear mites will scratch behind their ears and on their neck until there are raw sores. If you look in an ear infected with mites, you will see large amounts of brownish material that looks like coffee grounds. This is a combination of mite feces and earwax that the ear is producing in response to the irritation. Ear mites can be diagnosed and treated by your veterinarian.
Treatment involves flushing the ear canal to remove the debris and applying topical medication. Sometimes an injection is given to help kill the mites more quickly. If there are sores on the skin near the ears, antibiotics and anti-inflammatory medications might be given to help these heal. Cats don't get a lot of bacterial or yeast infections because their earflaps (pinnae) stand straight up, allowing air to get into the canal and help keep it dry. Some cats with allergies will have chronic ear infections, but this is much more common in dogs.
Ok, on to the canine creatures. Dogs can also be affected with ear mites. The symptoms and treatment are the same for dogs as for cats, as explained above.
More commonly, dogs are affected by yeast infections. Yeast is a normal inhabitant of the skin and ear canals of dogs. When the moisture and bacterial balance gets upset, an overgrowth of yeast can result. Yeast infections are characterized by brownish discharge and a foul odor. Sometimes yeast infections are complicated by a bacterial infection as well. The treatment for a yeast infection is to flush the ear canal and use topical medication for 10 to 14 days. Sometimes, oral medications must also be used. Dogs that swim a lot in the summer should have their ears cleaned with an appropriate cleaning solution after every swim or bath so that excess moisture is removed.
Bacterial infections are less common, thank goodness. Bacterial infections tend to be more severe and can cause significant pain. Sometimes the infection progresses to the point that the eardrum actually ruptures. It is advisable to obtain a culture from an ear that has a bacterial infection to determine the best medication for treatment. Bacterial infections typically produce copious liquid discharge that is tan, yellow, or even green. Sometimes, in severe cases, abscesses form under the skin below the ear.
Chronic or recurrent ear infections usually have some underlying cause. In dogs, the two most common causes are allergies and hypothyroidism. Hypothyroidism can be diagnosed with a blood test. Allergies can be more challenging to diagnose and treat because they have numerous causes. (see the related article “Allergic disease in dogs and cats”) Certain breeds of dogs are also more likely to develop recurrent ear infections. Most people know that Cocker Spaniels are notorious for ear disease. Also, breeds like Labrador Retrievers that spend a lot of time in the water are more prone to infections. The earflap laying down over the opening of the canal can trap moisture and block airflow to help create the perfect environment for overgrowth of bacteria or yeast.
One final complication related to ear infections that I would like to mention is the “aural hematoma”. This is a pocket of blood that forms under the skin of the earflap, usually in dogs with longer, floppy ears. Dogs that are scratching vigorously or shaking their heads excessively sometimes will break a small blood vessel under the skin. Because of the anatomy of the ear, the blood gets trapped between the skin and the cartilage of the ear. A puffy swelling results. Unfortunately, surgical drainage is required to repair this problem, so prevention is certainly the best option.
All in all, ear infections are caused by a limited number of factors. All should be diagnosed and treated by a veterinarian to prevent long-term consequences.
Please note that this information does not replace professional veterinary care. It is solely for educational purposes. Your pet's medical condition should be evaluated by a veterinarian before any medical decisions are implemented. If there is a potentially life-threatening emergency involving your pet, take your pet to a veterinarian or veterinary facility immediately.