How to deal with your cat’s ear infection (otitis externa)?

Among the various ear problems cats can have, just as in dogs, the most frequently seen ones are ear infections.

How do you recognise otitis in cats?

Cats tend to be stoic creatures that do not show readily when they are in pain, but because their ears are small, upright and open, you might spot an abnormal colour or smell easily. They might act a bit differently if they have an ear infection, for example:

• 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 cats get ear infections?

Cat 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. 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 and they are never due to one single cause, but instead the result of several combined factors.
Because their importance is variable, the causes for ear infections are usually divided into ‘predisposing’, ‘primary’, and ‘secondary/perpetuating’ factors.

Predisposing factors

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

• Conformation (abnormal ear flaps)

The cat breeds (Scottish Fold, Foldex, American Curl, etc) which have an ear shape different from the small, upright, triangular ear flap seen in wild cats and moggies are more likely to get ear infections. This is because the changes in the shape of the ears are caused by mutations that affect cartilage, a rubber-like tissue found in the ear flaps, the ear canals and other places in the body. A folded ear flap or narrower ear canal due to the mutated cartilage does not allow a proper ventilation of the ear. Heat and moisture trapped inside allow the skin microbes in the ear to increase their numbers.

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

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 from frequent ear cleanings or baths 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 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 them first. If your cat 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

Cats may occasionally get grass seeds, barley or wheat awns stuck in their ears. These hard objects rub against the skin and cause damage and swelling.

• Allergies

Cats with various hypersensitivities often may 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 in dogs, but fortunately they’re not common in cats.

• Various diseases

Other diseases that affect immunity can also cause cats to get ear infections easier. Among the most likely to do so are viral diseases like FeLV/FIV or FIP.

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, the ear has a good chance to heal.

• Microbes

All skin, including the one in the cat’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 and yeasts. 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 cat’s ears, like redness or discharge from them, or even only their 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 cat’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 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 drops, which is important not only for getting read of the infection as soon as possible and responsibly using the antibiotics, but also for your pocket - some special antibiotics, like the ones against Pseudomonas aeruginosa are more expensive than the routine ones.

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 irritations due to an allergic flare-up, 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 build-up of wax that often 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 the 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.

• 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. Please note this is 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 cat 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 cat avoid ear infections, after all prevention is a thousand times better than cure.

• Check your cat’s ears

Teach your cat from kittenhood that regular 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

If you notice mild to moderate wax build-up, but no redness or scratching, give the ears a gentle clean. Avoid cleaning your cat’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

Healthy cats do not really need bathing, but if they get soiled and really need washing, we recommend you dry their ears thoroughly after this with soft, absorbing materials and use only ear cleaners dispensed or recommended by a vet.

For any cat-related or ear-related questions (or both!) use the button to the right to book a call with us and, within 30 minutes, a friendly vet will answer them.