Ear infections in dogs are painful. Many dogs will shake their head and scratch their ears trying to relieve the discomfort. The ears often become red and inflamed and develop an offensive odor. A black or yellowish discharge commonly occurs. In chronic cases the ears may appear crusty or thickened and the ear canals often become narrowed (stenotic) due to the chronic inflammation.
Infection of the external ear canal (outer ear infection) is called otitis externa and is one of the most common types of infections seen in dogs. Some breeds, particularly those with large, floppy or hairy ears like Cocker Spaniels, Miniature Poodles, or Old English Sheepdogs, appear to be more prone to ear infections, but ear infections may occur in any breed.
There are three types of ear infections, known formally as otitis externa, media, and interna. The most common is
it’s important to prevent infections and seek early treatment when problems are detected.
Symptoms of ear infection vary, from a buildup of wax to discharge in the ear canal. Ear infections often cause significant discomfort, and affected dogs may show signs such as:
Ear mites are small arthropods belonging to the class Arachnida and the subclass Acari that live in the ears of animals and humans. The most commonly seen species in veterinary medicine is Otodectes cynotis (Gk. oto=ear, dectes=biter, cynotis=of the dog). This species, despite its name, is also responsible for 90% of ear mite infections in cats.
In veterinary practice, ear mite infections in dogs and cats may present as a disease that causes intense itching in one or both ears, which in turn triggers scratching at the affected ear. An unusually dark colored ear wax (cerumen) may also be produced. Cats, as well as dogs with erect ears that have control over ear direction, may be seen with one or both ear pinnas held at an odd or flattened angle.
Ear mites can cause several of these symptoms, including a black discharge, scratching, and head shaking. However, ear mite infections are more common in puppies and kittens. Adult dogs may occasionally contract ear mites from puppies or cats that are infected. Ear mites create an environment within the ear canal that often leads to a secondary bacterial or yeast (fungal) infection.
There are several kinds of bacteria and at least one type of fungus that commonly cause ear infections. Without knowing the specific kind of infection present, it is not possible to know which medication to use. In some cases, the problem is a foreign body, a polyp, or a tumor. Treatment with medication alone will not resolve these problems. It is important that your dog be examined to ensure that the eardrum is intact. Administration of certain medications can result in loss of hearing if the eardrum is ruptured. This can only be detected by a thorough ear examination by your veterinarian.
Otoscopic and microscopic examinations are the most common way to diagnose an ear infection, and determine a course of treatment. If there is a foreign body, wax plug, or parasite lodged in the ear canal, it will be removed. Some dogs must be sedated for this, or to allow a thorough ear flushing and cleaning. Many dogs will have more than one type of infection present (e.g., a bacterium and a fungus, or two kinds of bacteria). This situation usually requires the use of multiple medications or a broad-spectrum medication.
An important part of the evaluation is the identification of underlying disease. Many dogs with chronic or recurrent ear infections have allergies or low thyroid function (hypothyroidism). If underlying disease is suspected, it must be diagnosed and treated or the pet will continue to experience chronic ear problems.
Dogs with ear infections are uncomfortable. Their ears are a source of constant pain and they frequently scratch them and shake their head. This can cause a condition called an ‘aural hematoma,’ in which blood vessels in the ear flap break, causing a painful swelling that requires surgical treatment. Deep ear infections can damage or rupture the eardrum, causing an internal ear infection and even permanent hearing loss.
If not treated in a timely manner, a dog’s ear canal will eventually close. This is known as hyperplasia or stenosis. If the ear canal is swollen, it is difficult or impossible for medications to penetrate into the horizontal canal. Anti-inflammatory medications can sometimes shrink the swollen tissues and open the canal in some dogs. Most cases of hyperplasia will eventually require surgery.
There are several surgical procedures that are used to treat this problem. The most commonly performed surgery is called a lateral ear resection. The goal of the surgery is to remove the vertical part of the ear canal and to eliminate the swollen tissue from the horizontal canal. It is relatively easy to remove the vertical canal, but removal of large amounts of tissue from the horizontal canal is more difficult. In some cases, it is necessary to remove the entire ear canal (total ear canal ablation), which may result in permanent impairment of hearing.
If your dog or cat has an infection, it’s better to take care of it sooner, than later. Untreated ear infections are very painful and will eventually lead to hematomas (from scratching and shaking) and deafness.