A sore ear is a common problem for dogs. The ‘L’- shaped design of dogs’ ear canals allows debris, wax and moisture to accumulate within the ear and Dr Karen Davies writes that some breeds suffer more than others.

Long, ‘floppy’ ears (such as spaniels) with lots of folds and ears with a lot of hair growing in the ear canal are more likely to suffer problems.

A sore ear can be particularly distressing and the initial, treatable problem can quickly turn into something more serious with excessive scratching and head shaking.

To determine the cause of your pet’s problem it is best to see your vet as quickly as possible. Most infections occur in the outer part of the ear, in the canal and are called otitis externa.

Causes

There are many causes for ear problems, including injuries, bacterial infections, fungal (yeast) infections, grass seeds, dirt or sand, excessive wax production, soap or water in the ear canal, ear mites, allergies and other skin conditions.

Watch for one or more of the following signs:

• scratching one or both ears
• smelly ears
• head shaking
• head tilted to one side
• a discharge from the ear — it may be yellow, green, brown, black or cream
• painful ears or head when touched
• redness and inflammation of ear flap and ear canal
• swelling of ear flap
• stumbling or circling to one side
• lethargy and depression.

Diagnosis

Because most ear problems show the same signs, the ear canal and ear drum have to be examined with an otoscope for us to make a diagnosis.

For example, a grass seed in the ear may cause your dog to have exactly the same signs as a bacterial infection; we need to be able to see into the canals to tell the difference. The ear drum must be assessed, as a ruptured ear drum is a much more serious illness that can cause balance problems and inner ear infections. The medication we choose may be altered if the ear drum is ruptured. Some medications if given with a ruptured ear drum can cause temporary or permanent deafness.

Sometimes a smear is taken and examined in our in-house laboratory to check the cause of the problem and tailor the treatment to your pet’s needs. Other times a sterile swab is taken and sent out to a pathology laboratory to ‘grow’ the bacteria or yeast causing an infection, or to determine the best treatment, especially if we suspect an antibiotic resistance issue or unusual bacteria.

Some dogs that have chronic recurring problems (particularly if they are triggered by allergies), have bacteria or fungi that are resistant to the common ear ointments and drops, and need different formulations to treat the infection. This can only be determined with microbiological culture and sensitivity testing.

Occasionally sedatives or general anaesthesia is required if the animal is particularly painful or aggressive.

Medication and treatment

Medication may be given in the form of drops, ear cleaning solutions and tablets. It is essential these treatments are used correctly. Intermittent use of antibiotic solutions can favour the multiplication of resistant bacteria. This is why we always prescribe the drops for a certain time and recommend a revisit to check the ears at the end of the course. If the ears aren’t 100 per cent, then the problem will reoccur once the medication is stopped.

Sometimes more extensive treatment is necessary. For example, an ear that is full of pus may need to be flushed under general anaesthesia, to remove as much discharge as possible and assess the ear drum. Or a grass-seed must be removed under sedation or general anaesthesia to prevent rupture of the ear drum.

How can I prevent ear problems?

There are some things you can do:

Cut the hair around and inside the ear flap short to allow better circulation of air if your pet has a hairy, floppy-type ear flap.

Get your groomer to pluck the ears regularly to prevent matting and build up in the hair down into ear canal.

Use an ear cleaner once or twice monthly, or after swimming. This has antibacterial agents that protect against a broad range of infections. It also dissolves the wax and debris inside the ear and allows the dog to shake it out. It also dries out the ear if your dog has been swimming or water has gone into the ear during a bath. Do not poke things like cotton buds into your dog’s ears as you may cause further damage, including pushing wax or debris further down into the canal. Cotton wool and your finger is as small as you should go.

Control allergies. Allergies often cause or contribute to ear problems, as the inside of the ear is lined with skin, and skin is usually the primary organ affected with allergies in dogs and cats.

Infections in the middle and inner sections of the ear will not produce a discharge or an odour that is visible under most circumstances.

Otitis media is an infection of the middle ear. This is the section on the inside of the ear drum and contains the small bones that vibrate with sound and allow hearing. Infections in this section of the ear will not produce a discharge in the outer ear unless the ear drum is damaged.

When we look down the ear canal at the ear drum, the membrane of the ear drum is often cloudy and ballooning outward because of the fluid swelling behind it. These are often bacterial from the outer ear, foreign objects such as grass seeds, viral and can result from colds, flu, allergies, or infections migrating their way up from the throat. There is a small pressure relieving tube called the eustachian tube, the one that sometimes pops when you yawn or swallow. This allows the pressure in the ear to equalise when air pressure changes around us to stop the ear drum from perforating. On occasion, infections will track up this tube into the middle ear.

Clinical symptoms may include: pain in the head or neck, holding the neck in a guarded position, tilting the head, scratching at the ears (without otitis externa being present), yawning excessively, crying out in pain, ataxia/incoordination, facial paralysis, some loss of hearing, seizures, and fatigue.

Treatment will usually involve oral medication, as ear preparations cannot cross the intact ear drum. If the ear drum is damaged generally, the ear will be cleaned with sterile saline only because of the risk of causing hearing loss. Your vet may take a sample of the fluid from the internal chamber and send it to the laboratory to identify the specific bacteria and suitable antibiotic where an infection is suspected, to make the correct treatment choice. We will often also use some form of pain control to improve your dog’s comfort as this condition can be excruciating. Some animals may require surgery to remove all or part of the ear drum to allow relief of pressure and therefore pain, and to encourage drainage of infected fluids. The ear drum will usually grow back in a month with control of the infection.

Otitis interna is an infection in the innermost chamber of the ear. This section has several important functions and symptoms may include loss of hearing or balance, loss of appetite, nausea, head tilt, circling, leaning or falling toward the affected side, general incoordination, or spontaneous horizontal flicking of the eyes with the fast phase away from the affected side. Extension of infection from the inner ear to the brain leads to meningitis, meningoencephalitis, or abscesses.

Diagnosis is difficult as this chamber is part of the bony skull. X-rays can detect changes in the bony part of the bulb that makes up the inner ear and fluid may be suspected if the area is less ‘transparent’ than normal. However, more sensitive CT and MRI are preferred if feasible and will give a definitive diagnosis.

Otitis interna is a very serious condition. If your dog is unable to eat or drink normally due to nausea or disorientation, then hospitalisation for intravenous fluid therapy is generally warranted. Nausea must be controlled and dehydration avoided. Treatment will usually involve oral or injectable medications and in some instances surgery to drain the chamber and instil medication directly into the inner ear. This is a very complex surgery and often referral to a specialist will be advised.

Two potential long-term complications of inner ear infection include a permanently altered sense of balance and/or persistent signs of Horner’s syndrome. Your dog may also become permanently deaf in the affected ear.

That said, most dogs with otitis interna respond well to medical management. Expect a two- to four-month course of oral antibiotics to prevent a relapse. The altered sense of balance is typically improved within two to six weeks. Small dogs may recover their balance more quickly than large breeds. In recurrent severe cases, some dogs may have the entire inner, middle and external ear chambers removed (total ear ablation) to relieve their symptoms. Thankfully, this is very rare.

Fortunately, middle and inner ear infections are relatively uncommon compared to external ear issues.

As a side note, some dogs will shake their heads so violently they can cause bleeding between the layers of cartilage in the ear flap, which creates a pocket of blood called a haematoma. Small bleeds may resolve without drainage or surgery, larger ones may require surgical correction as well as the treatment of the ear irritation or infection.

Often the ear flap will scar leaving it thickened and looking more like a crinkle cut chip. Your vet is best to advise you on how to manage this and don’t be surprised if they delay surgery to let clotting to take place and bleeding to stop as well as allowing time to get the infection under control.

Veterinarian Dr Karen Davies owns and uses hunting dogs and has broadened her expertise to include animal rehabilitation, animal physiotherapy and animal hydrotherapy services. Readers of Field & Game Magazine can draw on her experience and expertise by submitting questions to editor@fieldandgame.com.au

Karen can be consulted at Direct Vet Services, 8/22–30 Wallace Ave, Point Cook, VIC; Email: directvetservices@bigpond.com or Tel: (03) 9369 1822.