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Ear Infections

Ear Infections

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Ingleburn Veterinary Hospital
Unit 4, 2 Noonan Road
NSW 2565

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02 9829 1947

Ingleburn Veterinary Emergency Centre
Unit 4, 2 Noonan Road
NSW 2565

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02 9829 1628

Otitis externa means inflammation of the external ear canal. It is very common in dogs, and cats can also be affected.


What are the symptoms?

A dog with otitis externa may show any or all of the following signs:

  • scratching at their ears, shaking their head, or rubbing their ears on the floor
  • red, inflamed ears and perhaps scaly skin
  • sensitive, or painful ears
  • an unpleasant smell
  • a dirty discharge inside the ear

Otitis can be very painful and distressing and won't get better by itself. Untreated, it can lead to serious problems such as haematomas and middle ear infections.


Why does it occur?

There is no simple answer to this question, because otitis is caused by a combination of factors: predisposing factors, primary factors and perpetuating factors. Predisposing factors are those that increase the risk of a dog developing otitis. This includes anything that limits movement of air in the ear canal, or creates a humid environment ideal for microbial growth. Droopy ears, hairy ears, narrow ear canals, too oily skin (seborrhoea), and frequent water in the ears are some common predisposing factors. However, just because a dog has erect ears doesn’t mean it can’t get otitis. German and Belgian Shepherds are at risk despite erect ears. Some general illnesses such as hypothyroidism can predispose to otitis by changing the normal function of the skin in the ear canals.

Primary factors that can directly cause otitis include allergy, ear mites, foreign bodies, tumours and overvigorous cleaning of the ear canal. Allergy is by far the most common primary cause of otitis externa in dogs, causing 90% of cases! Sometimes otitis is the only sign that a dog has an allergy, though usually they have dermatitis somewhere as well. The fact that most cases are caused by allergies means many dogs with otitis will get recurring episodes.

Perpetuating or secondary factors will worsen and prolong the inflammation of the ear and include bacterial and fungal infections, and permanent changes in the diameter of the ear canal due to many episodes of otitis. Therefore these factors need to be treated alongside the primary causes of otitis.



As well as finding out the patients history, we need to examine the ears. This includes looking inside the ear canals with an instrument called an otoscope. Because some cases of otitis can be associated with dermatitis or allergies, we may also want to look at the rest of your dog’s skin – after all, the ear canal is really just a specialised type of skin. The type of treatment used will be different according to what we find.

Occasionally the cause is obvious – for instance ear mites can often be seen directly with the otoscope, though ear mites are rare in adult dogs. We will need to take a swab of the discharge for cytology. We prepare and stain a slide of the discharge, and examine it under a microscope looking for bacteria or fungi. This test can be done while you wait, and will usually tell us whether there is infection present. If we see a particularly nasty bacterial infection, we may recommend sending a swab to a pathologist for culturing.


We have to treat the predisposing, primary and secondary causes in each case. For instance, a tumour or foreign body lodged in the ear canal would need to be removed. Infections need to be treated with ear cleaning and antibiotic tablets or drops. The products used to treat otitis externa may be any of the following:

An antibiotic - to kill harmful bacteria

An antifungal - to kill harmful fungi

An acaricide - to kill ear mites

An anti-inflammatory - to reduce pain and swelling

These will usually be as ear drops. As well as the ear drops we will often recommend that you use a cleansing solution to remove excess wax and debris from the ear canal. Without proper cleaning, it is often impossible for the ear drops to properly penetrate the ear canal and do their job. This is one of the most common causes of failure in the treatment of otitis. We may sometimes prescribe oral antibiotics, antifungals or anti-inflammatory tablets too.

Never use cleaner or drops not prescribed for your pet. They may be inappropriate and even harmful to the ear.


How to treat your dog’s otitis externa

Done properly, the treatment of your dog’s ears will take only a few minutes each day and will ensure the fastest possible resolution of the problem.

Cleaning the ear:

Warm the solution by standing it in a bowl of warm water. Then lift the ear flap and apply liberally directly into the ear, until it overflows. Gently massage the vertical canal between your thumb and forefinger. (The canal can be felt as a large solid tube lying just under the skin below the base of the ear). Massage for 10 to 20 seconds to break up the wax - you should hear a squelching noise as you massage. Unless the ear is really sore, your dog may even enjoy this, because they've been trying to scratch this spot for ages!

Next (if they haven’t done it already!) let your dog shake its head and shake out some of the dirt and wax from the ear canal. You probably want to be outside when you do this! Then, get some cotton wool and wipe away the visible dirt and wax. Repeat this process until the fluid coming out no longer looks dirty.

How often you do this depends on how dirty the ears are and how bad the infection is, but usually we recommend once daily for 2-3 days and then twice weekly until the problem is resolved.

If you are very careful you can use a cotton bud to clean the skin folds around the base of the ear, but never put a cotton bud into the ear canal itself – you’ll just push the wax further in!

Ear drops:

It’s advisable to wait 15 minutes after cleaning before putting the ear drops in. If you don’t, the drops will be diluted and shaken out with the cleansing solution.

Shake the drops well before use. Then lift the ear flap and apply the drops directly into the ear canal and work them in by massaging the base of the ear. We can show you how to do this. The label on the bottle will tell you how many drops to use. Normally you'll use them twice daily for 14 days, but it differs depending on the type of drops being used.

Follow the directions on the label!


Summary of treatment plan:

Use medication according to the label directions.

Use the ear cleansing solution daily for a few days and then twice weekly.

For most cases (with the exception of ear mites), we say use the drops for 14 days, then get a recheck

Don’t stop treating until we say you can!

Make an appointment for a recheck as soon as the treatment course is finished.

Rechecks are very important!

For most cases of otitis externa, it is very important that you bring your dog back for us to recheck the ears. Some cases may require a longer course of treatment for a complete cure, and you will not be able to tell this yourself. Many ear drops contain anti-inflammatory drugs that will take away the redness, swelling and soreness, but if the infection itself hasn’t resolved, the problem may recur soon after you stop treatment. And when it comes back next time, it’s much harder to know how to treat the problem, if we don’t know how well the medication worked the first time!

If everything seems to be going OK, we suggest you stop using the ear drops 1-2 days before you come in for the recheck. If you are using a cleansing solution, you can use this right up to the day before the recheck. But don’t put anything in the ear on the day, as we’d like to examine the ear without any wet, oily ear drops in it.

So please don’t forget to bring your dog back for his/her recheck. If there is still a problem, we can continue or change the treatment. Some cases are chronic and need rechecks every 2 weeks for some time.

Preventing a recurrence of the problem:

Check the ears regularly - weekly in problem cases.

Come back for a consultation at the first sign of problems before the infection gets too bad.

Avoid water entry into the ears during bathing

Don’t pluck hair from the ears. For dogs with very hairy ears, clipping it short may help.

Problem Cases:

In severe cases, including those where other problems are suspected, or where there is poor response to treatment, we may recommend one of the following:


  • Anaesthesia – to clean and examine the ear canal.
  • Culture & Sensitivity – by taking a swab from the ear and sending it to the laboratory, we can identify exactly what type of bacteria is in the ear. We can then use the most effective antibiotic to kill it.
  • Using a cleansing solution once or twice a month or sooner if the ears start to look dirty.
  • Assessment for allergies - eg. Atopy & food allergy.
  • Pulse treatment with antibiotics.
  • Surgery – may be required in severe cases, to alter or even remove the ear canal, but this is very rare.
  • Referral to a dermatologist