Ear Diseases in Dogs: Ear Infection, Symptoms and Ear Drop Treatment

Medically reviewed by: Kinga Wojtczak, Doctor of Veterinary Medicine, specialist in canine and feline diseases

Ear diseases are a very common problem in dogs. They vary in cause and severity, but from a clinical point of view, inflammatory ear diseases in dogs are the ones most often seen. Other conditions that can affect dogs' ears include:

• traumatic lesions, such as an aural hematoma (hematoma of the ear flap),
• tumors (neoplastic lesions),
• lesions of parasitic origin.

In this article, you will learn how to tell that something is wrong with your pet's ears. I will also explain how ear diseases in dogs are treated and what you can do to prevent them.

How is a dog's ear structured?

As in humans, a dog's ear consists of 3 parts:

• the external ear,
• the middle ear,
• the inner ear.

The external ear consists of the pinna (ear flap) and the ear canal.

The middle ear is an air-filled space that contains structures such as:

• the tympanic membrane (eardrum),
• the tympanic cavity,
• 3 auditory ossicles (the malleus, incus and stapes),
• the auditory (Eustachian) tube.

The inner ear, on the other hand, is the most complex part of the ear and contains:

• the auditory nerve,
• 3 semicircular canals,
• the cochlea.

Causes of ear diseases in dogs

Inflammation of the external ear (otitis externa) is a chronic inflammatory disease of the external ear canals. Factors that predispose to this condition are excessive moisture and impaired ventilation. This inflammation occurs in humans, cats and dogs alike. Breeds with long, pendulous ears, such as Cocker Spaniels, are the most at risk.

Predisposing factor	Characteristics
Ear conformation (shape)	heavy ears, pendulous ears, ears with a narrow ear canal, hair in the ear canal.
Excessive moisture	frequent bathing, frequent swimming, humid environment.
Improper treatment	excessive treatment, insufficient treatment, inappropriate treatment.
Iatrogenic irritation	excessive ear cleaning, injuries caused by cotton gauze pads.

Products that contain both antibiotics with antibacterial action and substances with antifungal action are now widely available. However, an ear swab should first be taken for culture and susceptibility testing, so that a product containing the antibiotic to which the bacteria are most susceptible can be used. Treatment consists of applying ear drops twice a day for 12–14 days.

After this period, it is a good idea to have your veterinarian perform a follow-up otoscopic examination to make sure the treatment has been effective.

Aural hematoma

Other ear conditions can arise as secondary or primary diseases. An aural hematoma very often develops secondary to ear inflammation. The itching that accompanies ear inflammation contributes to blunt trauma to the pinna during head shaking, which results in a hematoma. A hematoma makes the pinna look like a ping-pong ball. It forms when a blood vessel ruptures.

The blood that collects in the pinna clots and is resorbed, and the remaining fibrin leads to deformation of the pinna. That is why treatment is based on promptly draining the blood from the pinna and cleaning out the resulting cavity of fibrin and clotted blood.

Parasites

Ear diseases can also be caused by parasites. In dogs, we often see Demodex mites, mange mites and even ticks, which can contribute to ceruminous (waxy) otitis externa.

Foreign bodies

Inflammation caused by foreign bodies is not uncommon, especially in animals that roam through tall grass and forests. It presents as unilateral inflammation of the ear canal, and during an otoscopic examination of the ear canal we may find blades of grass, grass awns (foxtails) or small stones. This examination should be performed very carefully, because the increased amount of discharge in the ear masks the foreign body, which in this situation is very easy to miss.

Allergies

Today, rapidly developing laboratory diagnostics allow us to diagnose ear inflammation caused by allergies and hypersensitivity. In 50–80% of dogs, bilateral otitis externa results from atopy, which is accompanied by other skin signs. In 3–5% of dogs with atopy, otitis externa is the only sign. We quite often see animals with a food allergy. In 80% of dogs with a food allergy, ear inflammation occurs as one of many signs, while in 20% it may be the only sign.

Many drugs used to treat animals can irritate the ear canals, e.g., neomycin and propylene glycol. Such substances can lead to a contact allergy and, ultimately, to inflammation of the ear canals. This inflammation develops shortly after the sensitizing substance is used. Treatment of hypersensitivity-related inflammation consists of feeding a hypoallergenic diet, removing allergens from the environment as far as possible and starting steroid therapy.

Other causes

Ear diseases often affect Labradors. Ear inflammation in this dog breed is difficult to treat and often recurs. Keep in mind that Labradors are predisposed to hypothyroidism. Dogs with this endocrine disorder very often have long-standing ear problems. Inflammatory polyps are rare in dogs but more common in cats.

They are usually unilateral and arise from the lining of the tympanic cavity, the tympanic membrane or the nasopharynx. The only treatment is surgical removal of the polyp. Tumors are rare. Most often we diagnose adenomas or adenocarcinomas arising from the ceruminous (wax-producing) glands, papillomas, or squamous cell carcinomas and basal cell carcinomas. The last two are malignant tumors, which often recur after surgical removal.

Complications of ear inflammation

The main consequences are blunt trauma to the pinna and to the opening of the ear canal. The resulting wounds often become infected, or blunt trauma may lead to the previously described aural hematoma, which causes deformation of the pinna. In severe and chronic cases that are left untreated, hyperpigmentation with hyperkeratosis of the ear canals develops, leading to narrowing of the ear canal and, at the final stage, to deafness.

In such cases, there are surgical methods that involve widening the canal by ablating it. Inflammation lasting more than 2 months leads to inflammation of the middle and inner ear (otitis media and otitis interna), which manifests as vestibular syndrome.

Symptoms of a dog ear infection

Common signs of ear inflammation are itching and pain around the ear.

You may then notice the following in your dog:

• head shaking,
• rubbing the head against objects or the floor,
• scratching at the ears,
• whining.

Foul-smelling discharge builds up in the ears, and its odor may be specific to the causative agent. In acute cases, the pinna and the ear canal are red and swollen. The ear canal may be covered with ulcers and erosions, while the pinna may be scratched, with thinning hair and crusts. In chronic cases, lichenification, hyperkeratosis and scarring of the pinna develop, and the ear canal may become narrowed or even completely closed.

When inflammation of the external ear (otitis externa) is left untreated, the inflammation spreads to the inner ear, which manifests as vestibular syndrome. In such cases, we see a head tilt toward the affected ear and sometimes circling. In the treatment of ear inflammation, targeted therapy is very important, because the inflammation may be caused by fungi, yeasts or bacteria.

The fungi most commonly isolated from ear swabs include Malassezia, while the bacteria most commonly isolated include Pseudomonas and Staphylococcus.

Diagnosing a dog ear infection

Clinical signs together with an otoscopic examination allow us to diagnose ear inflammation with 100% certainty. What matters is identifying the cause. For this, a history taken from the owner is very helpful, as are a microscopic examination of the ear discharge (ear cytology) and a culture, which will allow us to determine whether the inflammation is caused by bacteria or fungi.

If the test results are negative, additional laboratory tests should be performed:

• allergy testing,
• endocrine testing,
• scrapings, in which we may find a parasite.

Anal gland problems in dogs are also worth keeping in mind. The secretion that builds up in the anal glands is itch-inducing for the ears, but it does not cause inflammation. That is why, before making a final diagnosis, it is a good idea to examine the anal sacs and express (empty) them if they are overfilled.

Treating a dog ear infection

Treatment consists of using ear drops twice a day for at least 2 weeks. The therapy must be targeted at the specific agent causing the inflammation, which is why a correct diagnosis is so important. After all, we do not want to treat bacteria with antiparasitic drugs… When ear inflammation is a sign of another disease, as in allergies or hypothyroidism, we treat the underlying disease.

Flushing the ear canals is rarely necessary. If it is needed, however, antiseptic solutions diluted in warm water are used for it. This cleaning procedure is performed with the animal under sedation (premedication).

Medications for a dog ear infection

Commonly used ear drops include:

• Dicortineff-vet,
• Surolan,
• Orilan,
• Aurizon.

These drugs have antibacterial, antifungal and antipruritic (anti-itch) effects, which is why the treatment is visibly effective after just a few days of use. In ear diseases of parasitic origin, you should use a drug that eliminates the parasite in question.

How can ear diseases be prevented?

When you decide to get a dog, it is a good idea to read about the traits of its breed. The anatomy of purebred dogs, or of mixes of particular breeds, makes them more likely to develop ear diseases. This is exactly the case with ear inflammation. It often affects Cocker Spaniels, Labradors and Golden Retrievers, that is, dogs that like to swim or have pendulous ear flaps.

With this knowledge, we will be able to prevent ear inflammation by:

• drying the ears,
• airing out the ears,
• proper care.

Remember that caring for our pets' ears is much cheaper than treating them. If you want to learn how to do it correctly, I encourage you to read the article "Cleaning dog and cat ears: how to clean them and what to use". Do you have questions about this topic? Ask them now by posting a comment below the article.

FAQ