Ear infection - Otitis externa

Dogs ear being shown

What is otitis externa?

This very common problem occurs when the lining of outside part of the dog’s ear (from the ear flap and along the ear canal to the ear drum) becomes inflamed and thickened in either one or both ears. This condition can be uncomfortable and very painful and, if left untreated, may require surgery to treat.

Which dogs are more at risk?

Otitis externa can affect any dog, regardless of their age or breed, although it may be more likely to occur in long-eared dogs, such as spaniels, retrievers, or dogs with very hairy ears. Dogs with otitis externa can go on to develop inflammation of the middle ear (just behind the ear drum) or in very severe cases, the inner ear (where the ear and brain meet).

Why are ear infections common in dogs?

Dogs have a long and narrow ear canal with an L-shaped right angle bend part the way along. This bend is a common site for waste to collect, leading to problems in the ear. Dogs with long ears can have a higher risk of developing otitis externa because the ear flaps prevent moisture from escaping, making them a warm wet environment, perfect for yeast and bacteria to thrive and spread.

What effects should I look out for?

Initially the effects may be mild, but can quickly get worse if left untreated. Clinical signs of otitis externa can include any combination of the following:

  • head shaking (especially if given an ear rub)
  • the underside of the ear may be red or inflamed, and may feel warm
  • repeatedly scratching or rubbing the ear (sometimes causing bleeding)
  • the ear smelling unpleasant
  • your dog may not want to be touched on the head or around the ear
  • apparent pain
  • waxy (brown, yellow or black) discharge
  • your dog may seem tired or irritable (due to them being uncomfortable)

In severe or chronic cases, the outer ear canal can thicken and the eardrum can rupture causing problems in the middle or inner ear, which may cause the dog to be off their food, find it difficult to walk in a straight line/stand up and tilt their head. They may be in severe pain and can become deaf.

What causes otitis externa?

A mixture of several different factors may lead to your dog developing otitis externa. Certain triggers may cause your dog’s ear to become more susceptible to other influences, such as yeast, bacteria or foreign bodies. These secondary factors can then cause inflammation, irritation and pain.

The initial triggers can include:


One of the most common underlying causes is allergies to food or something in the environment, leading to inflammation or itching of the ear.
Find out more about food allergies.

The environment

Humid weather, swimming and foreign bodies from walks in wooded areas or grass land can all set the stage for further ear problems. 

The shape of the dog’s ears

Dogs with larger, hanging ears may be more prone to otitis externa due to the ear flaps keeping warm moist air and foreign bodies in the ear canal, making it more susceptible to secondary factors.


Tumours in the ear may shut in moisture or foreign bodies which encourage yeast and bacteria to grow.


Ear mites may cause the ear to become inflamed and itch, leading to a secondary infection.

Other medical issues

Adverse reactions to drugs, autoimmune diseases, a build-up of dead skin (keratinisation) or hormonal disorders can all lead to environments suitable for yeast or bacteria to take hold.

Overenthusiastic cleaning

Cleaning your dog’s ears too roughly or cleaning incorrectly can cause irritation or debris to be pushed further into your dog’s ear.

What should I do if I suspect my dog has otitis externa?

If you think that your dog has any form of ear irritation or infection, you should speak to your vet straight away. The sooner appropriate treatment is started, the sooner your dog can be given relief from the itching and pain. Otitis externa can get progressively worse, so not seeking advice is likely to make the condition more painful and more difficult to treat. Do not try and treat your dog at home or clean your dog’s ear if you do not know what’s causing the irritation. If your dog has a foreign body in their ear you may accidentally push it further into their ear causing more damage.

How is this condition diagnosed?

After taking a full history your vet will want to look inside your dog’s ear canal to look at the degree of inflammation and see if there are any tumours, foreign bodies etc. that could be causing the irritation. A swab may be taken from your dog’s ears to look for yeast, bacteria or parasites. Your vet might also want to investigate if your dog has any allergies or any underlying health conditions that could have caused this.

What treatment might my vet give?

The treatment your vet decides to give your dog will depend on what they find during their examinations and investigations.

  • Your vet may clip away any long fur around the ear or may clip the fine hairs in the ear canal to increase air flow and allow any damaged tissue to heal
  • Your vet will clean your dog’s ears and any foreign bodies or blockages in the ear will need to be removed. Your dog may need a thorough ear flushing and cleaning, which may require them to be sedated or anaesthetised 
  • If appropriate, medications will be given for parasite, bacteria or yeast infections and certain treatments may be required to reduce the swelling or treat the pain 
  • Dogs that have allergies may require certain drugs or a change in diet/lifestyle, depending on what they are allergic to. Dogs that have a tumour or have severe otitis externa may also require surgery

Recovery from otitis externa will largely be at home, but how long this takes will depend on how severe the damage is. Most dogs will fully recover in three to four weeks, but severe cases may take longer.

Treating the initial cause

Most ear infections can be managed and treated successfully so long as the initial trigger is discovered and treated. If the initial cause is left untreated your dog may keep getting secondary infections until the trigger is eliminated, which can lead to the ear canals narrowing, and infection in the middle or inner ear. Scar tissue can form in the ear canal and may prevent some medications from reaching the problem tissue, whilst also preventing skin, cells and hairs from leaving the ear, causing further problems.

Taking steps to prevent otitis externa

To try and prevent further instances of otitis externa you should regularly clean your dog’s ears. Some dogs may be more prone to chronic otitis, and regular cleaning is unlikely to prevent this. It’s best to get into a routine of doing this and choosing one day a week where you can take a few minutes to do a quick check and a quick clean. Dogs with very hairy ears should be trimmed often to prevent heat and moisture becoming trapped in the ear which could cause further problems. If your dog regularly goes swimming, ensure that you dry your dog’s ears afterwards.

How to clean your dog’s ears

Ask your vet to show you the best way to do this. It is important that you clean your dog’s ears correctly and do not push anything into the depths of your dog’s ear canal in case it damages the ear, pushes particles deeper inside the ear or triggers an infection.  

  • Massage the base of your dog’s ears for around 20 seconds to soften and release any material. You may wish to consider using a suitable dog friendly ear cleaner to make this more effective (talk to your local veterinary practices to see which ones they recommend)
  • Wipe the inside part of your dog’s ear flap several times with a cotton ball or wet wipe, starting at the entrance to the ear canal and moving toward the tip of the ear so as to drag any material away from the ear canal. Dry the ear gently with a towel afterwards

Think your dog may be affected?

If you're worried about your dog's health, always contact your vet immediately!

We're not a veterinary organisation and so we can't give veterinary advice, but if you're worried about any of the issues raised in this article, please contact your local vet practice for further information.

Find a vet near you

If you're looking for a vet practice near you, why not visit the Royal College of Veterinary Surgeons' Find a vet page.