How to deal with your dog's ear infection (otitis externa)

There’s an entire host of ear problems often seen in dogs, but ear infections are probably the most common one. As you will see from this article, otitis externa is not one well-defined disease, in the strict sense of the word, but it is easier to approach it as such.

How do you recognise otitis in dogs?

Some dogs manage to hide having an infected, sore ear for a while, though the majority will let you know that something is not right straight away.

Here are some behaviours that you may see:

• shaking their head a lot more than usual,

• scratching at their ears all the time,

• rubbing their head/ears on furniture or the floor,

• head-tilting, though this is often subtle,

• crying out when they scratch at them or when their ears are rubbed,

• not hearing that well.

The inside of the ears themselves might be:

• red, hot, and/or swollen,

• smelly, often with a sharp, acidic odour,

• dirtier than usual, filled with dark wax,

• moist instead of dry,

• covered with white scabs or yellow crusting.

How do dogs get ear infections?

Dog ears, just like ours, are protected by the healthy skin lining them, the fine hairs growing at their entrance (stop larger things from getting into the ear canal) and the wax (traps smaller particles and microbes). Wax is produced deeper in the ear canal by glands in the skin and is slowly pushed by jaw movements towards the outside where it dries and crumbles off. This is called the ‘self-cleaning mechanism of the ear’.

Ear infections often happen when this self-cleaning mechanism is slowed down or falls completely still. They are never due to one single cause, but are the result of several combined factors, grouped into ‘predisposing’, ‘primary’, and ‘secondary/perpetuating’ factors.

Predisposing factors

These do not cause otitis on their own, but they make the dog more likely to get it, being the ones most likely to affect the self-cleaning mechanism. The most common are the ones below.

• Conformation (long and heavy, floppy ear flaps; hairy or narrow ear canals)

The hanging ears of Spaniels, Bassets, Beagles or Setters, the excessively hairy ears of curly breeds like Schnauzers, Bedlingtons, Poodles and their crosses, and the narrow ear canals of Pugs, Bulldogs, Shar-Peis and Chow Chows reduce ventilation of the ear and help trapping heat and moisture inside the ear canal. This allows the skin microbes in the ear to increase their numbers.

• Maceration (frequent bathing or swimming or using water-based ear cleaners)

Some breeds like Labradors, Retrievers, Water Spaniels and Setters are big fans of water and regularly swim, getting lots of water in their ears. Also, a lot of shop-bought ear cleaners are water-based. Using them does not dissolve the wax which is oily, but only makes the ear(s) wet. Wetness softens and weakens the dry, tight top layer of the skin and reduces its function as a barrier.

• Irritation (excessive ear cleaning, using harsh materials, hair plucking)

Even using the right type of cleaner, but too often (remember the self-cleaning mechanism!) or too harshly, or (having the groomer) plucking the hairs in the ears can cause irritation. Irritation leads to swelling and this, just like wetness, causes the dry, tight top layer of the skin to unravel and lose its protective barrier function.

Primary factors

They are always present, but sometimes it may be possible to treat the ear infection without having to treat the primary factors first. If your dog gets ear infections frequently, then dealing with them becomes paramount.

• Parasites

The most commonly seen with ear infections are the ear mites (Otodectes cynotis), but other types of external parasites can be involved as well because their bites and the resulting swelling damages the skin barrier.

• Foreign bodies

Dogs occasionally get grass seeds, barley or wheat awns, sand and soil in their ears during walks. These hard objects rub against the skin and cause damage and swelling.

• Allergies

Dogs with various hypersensitivities often have ear problems. The skin in the ear is not that different from the rest of the body (apart from the wax production), and it suffers the same effects of the allergies.

• Keratinisation disorders

These are conditions that affect how thick and tight is the top layer of the skin or how much grease the skin glands produce. There are many of them, but seborrhea is the one we sometimes see contributing to ear infections.

• Various diseases

Other diseases that affect skin quality and immunity can also cause dogs to get ear infections easier. Among the most likely to do so are ringworm, hypothyroidism and Cushing’s disease. Lumps in the ear canal can also act as a factor for infections if they get big enough to close the canal.

Secondary or perpetuating factors

These are the factors that maintain the problem, so they are the main target of the treatment. Once these are solved and the primary factors under control, the ear has a good chance to heal.

• Microbes

All skin, including the one in the dog’s ear is covered with a mixed population of microbes: bacteria, yeasts, fungi and viruses. In small numbers, they do not cause problems, but if the skin is not healthy or the wax layer builds up, they get a chance to grow in large numbers and cause infections. This means that most ear infections are caused by ‘normal’ for the skin bacteria like various Staphylococcus species and yeasts like Malassezia pachydermatis. Occasionally, a foreign bacterium called Pseudomonas aeruginosa can be involved.

• Deeper infections

What we normally call ‘the ear’ is in fact only the external ear, a continuation of the middle ear (an air-filled chamber sealed off by the eardrum) that acts as a link to the inner ear (another sealed-off space in the skull, containing the hearing organ proper). Untreated infections of the middle or inner ear usually keep spilling out into the external ear.

• Chronic changes in the ear canal

This a very unfortunate effect of repeated, especially incompletely or altogether untreated ear infections. Skin that is irritated and swollen for a long time becomes permanently thickened and sheds its top layer abnormally. In the ear canal, this means further narrowing and predisposition towards continuous infection. On top of this, the thickening affects the wax production and its clearing, completely throwing off the normal balance.

When to see your vet

Whenever you notice anything abnormal about your dog’s ears, like considerable redness or discharge from them, or vigorous scratching and rubbing at them, it is a good idea to have them checked by your vet.

If you are still not sure if the state of the ear(s) warrants a visit to your registered vet, or have more ear-related questions, then please make an appointment with one of our FirstVet vets using the button below this article. Within 30 minutes you’ll get friendly and professional advice from one of our vets.

What to expect at your vet’s?

The first thing vets do when presented with ear complaints is have a thorough look at the ear canal and the eardrum with an otoscope. Sometimes, if your dog’s ear is too sore to allow a check awake, or too dirty to be seen properly and needs cleaning first, your vet will recommend doing this under a short general anaesthesia. This will also be the case when your vet suspects/sees a foreign body or a mass in the ear canal that they need to remove or take a sample from.

The next step is usually taking a smear of the wax to check for the microbes present (they are recognisable by their different sizes, shapes and stains that they absorb) and their numbers. Depending on personal preference, but mostly on the particulars of the infection, the vet will look at the smears under the microscope themselves or send them to external laboratories, which can also culture the microbes.

Knowing which microbes are causing problems helps the vet choose the correct ear drops. This is important not only for getting rid of the infection as soon as possible and responsibly using the antibiotics, but also for your pocket - some special antibiotics, like the ones effective against Pseudomonas aeruginosa are more expensive than the routine ones, and using them can be avoided if the smear shows this microbe is not present.

The smear is recommended even if the ear is clean. A red, sore, itchy ear without much wax build-up or with minimal numbers of microbes can be seen with allergic flare-ups, in which case the treatment needs to include allergy management as well.

If your vet suspects a middle or even an inner ear infection, they usually take a head x-ray to confirm or rule this out.

Medication-wise, you’re likely to come home with a combination of the following:

• an oil-based ear cleaner

This removes the wax build-up that harbours the bacteria and yeasts. Please do not confuse it with the ear drops below. A cleaner is used first, then removed from the ear canal after 5-10 min and then the medicated ear drops applied and left in.

• ear drops

These come in different versions, some only contain small amounts of steroids to reduce inflammation (usually dispensed when the soreness is only due to allergies), but most will also contain antibiotics and antifungals besides the steroids.

Some ear drops are applied twice a day, some once a day, generally for 5-7 days, your vet will advise you on that. There are some new treatments available now that are not liquid drops, but gels applied in the ear once or twice (a week apart), after an initial cleaning of the ear at the vet. In this case, it’s important not to clean the ear at home at all, or you will remove this long-acting medication. Your vet will advise you if this is the case.

• painkillers

Ear infections, especially the severe or repeated ones, can be very painful, so your vet might prescribe pain relief, either as a liquid or tablets.

• anti-parasitic spot-on

If your pet has ear mites and your regular parasite prevention does not work against them (not all do), you might get an additional anti-parasitic, usually a spot-on. This spot-on has to be applied on the skin at the back of the neck as usual, not in the sore ear!

For ears with chronic changes, very thickened, narrow and constantly sore ear canals, the only remaining treatment able to spare the dog a continuously painful ear is surgery to remove the ear canal permanently. To avoid this, vets recommend promptly treating all ear infections and their underlying causes.

What can you do to prevent your dog from getting ear infections?

There are a lot of things that you can do to help your dog avoid ear infections, after all prevention is a thousand times better than cure.

• Check your dog’s ears

Teach your dog from puppyhood that daily ear checks are facts of life. This will not necessarily prevent an infection from settling in, but it will help you spot it early and get it treated before it becomes too severe.

• Keep their ears clean and ear canals open

Since they are innate, breed-related traits, you can’t do much about long ear flaps or narrow and hairy ear canals, but you can keep the hairs clipped as short as possible. Ask your groomer to clip the hairs instead of plucking them. You can also do the clipping at home, using rounded-tips baby scissors.

Please note that ear cropping does not help reduce the number of infections, but actually increases it.

If you notice mild to moderate wax build-up, but no redness or scratching, give the ears a gentle clean. Avoid cleaning your dog’s ears for long periods of time or longer than recommended by your vet and always be gentle when cleaning them.

• Keep the ears dry

While we wouldn’t dare suggest robbing your dog of the joy of swimming, we recommend you dry their ears thoroughly after each bath or swim with soft, absorbing materials and use only ear cleaners dispensed or recommended by a vet.

For more ear-related or unrelated questions, please use the button to the right of the page to book a consultation with us and, within 30 min max, one of our vets will provide you with all the answers you need!