External ear infections (otitis externa) are common in dogs and can cause considerable pain and discomfort.

What causes ear infections in dogs?

They are caused by an overgrowth of bacteria or yeast within the ear canal, resulting in inflammation, pain and itchiness. There are various underlying causes that can include foreign bodies (e.g. grass seeds), skin allergies, hormone imbalances, ear mites and excessive earwax. A grass seed stuck down the ear is a common reason for an ear to be suddenly very itchy and this normally follows on from a walk. Most dogs will need a sedation or general anaesthetic for it to be removed as it can be a bit fiddly!

Certain breeds are also more prone to ear infections – they tend to be those with larger and floppy ears and those with hairy ear canals. These predisposing features can make it more difficult for air to get down into the ear canal, making it a more favourable environment for bacteria to grow. Ear infections can therefore be recurrent, with some dogs regularly suffering from infections. In dogs that are prone, swimming can increase their risk of a flare up, as water gets down into the ears making it a perfect environment for bacteria.

What are the signs of an ear infection in dogs?

The typical signs are:

• Head shaking
• Scratching at the ear(s)
• Rubbing the ear on the ground
• Pain when the ear touched or examined
• Skin around ear canal is inflamed (red), swollen and warm to touch
• Scabs and crusts may be present
• Discharge may be present (can vary in colour and smell)
• An aural haematoma may form (this is a secondary problem where the scratching/rubbing causes damage to blood vessels within the ear flap, resulting in bleeding inside the flap and swelling)
• Head tilt may be present

Most ear infections are limited to the external ear canal, but in severe cases the middle and inner ear can also be affected. This can cause additional signs including dizziness and loss of balance, a head tilt to one side and partial deafness.

How are ear infections in dogs diagnosed?

External ear infections are usually simple to diagnose based on the clinical history and physical examination. It can be more difficult to diagnose middle and inner ear infections – these may need further tests such as x-rays and a camera being inserted down the ear canal.

You vet may advise that a sample is taken from the ear using a swab and that this is sent to the lab to ensure they are using the correct treatment for the type of infection. This is especially important with long-standing (chronic) or severe ear infections. In these cases, it is also especially important to consider any possible underlying causes, such as skin allergies. Dogs with skin allergies are more prone to ear infections, and interestingly they tend to also be foot chewers! They may be allergic to something in their diet or an environmental allergen such as dust mites or pollens. So have a chat to your vet if your dog is displaying these signs.

What are the treatment options for ear infections in dogs?

The following treatments may be used when dealing with an ear infection:

• Medicated ear drops: these usually contain a combination of an antibiotic (to treat bacterial infection), an anti-fungal (to treat yeast overgrowth) and a steroid to reduce inflammation, swelling and pain. There are lots of different brands available so your vet will choose the one that they feel is most suitable. They work really well, especially for simple infections.
• Ear cleaner: this is especially important where there is lots of discharge in the ear canal. Your vet will advise you on the best cleaner to use and will demonstrate the technique. Do not use cotton buds down the ears.
• Anti-inflammatory pain relief: if your dog is in lots of pain then your vet is likely to prescribe some additional pain relief.
• Antibiotic tablets: severe infections may need to be treated with oral antibiotics. In some cases (particularly if they are chronic) then the ear canal can be very swollen and it can be very difficult for ear drops to penetrate and do their job, as the ear canal is effectively closed. Also, these infections tend to be very painful, and so dogs will often not tolerate handling of the ear and topical treatment at this stage.
• Treating the underlying cause: as discussed, the underlying cause must also be treated. For instance, if there is a grass seed this must be removed, or if the dog has a skin allergy then this should ideally be managed to reduce the recurrence of ear infections. 

What is the prognosis for dogs with ear infections?

If caught early then external ear infections are usually straightforward to treat. If the infection is chronic or there are resistant bacteria then it can be much more difficult. Occasional, surgery is recommended in order to remove the external ear canal entirely. While this is a major operation, it can drastically improve the quality of life in dogs that are constantly plagued by chronic infections.

What can be done to reduce the chances of ear infections in dogs?

There are various measures that can be taken to reduce the frequency of ear infections in dogs that are prone to infections. They include:

• Checking the ears regularly to catch infection early. Your vet can show you how to do this.
• Drying the ears after swimming or avoiding the water entirely if ear infections are a big problem.
• Cleaning the ears. If your dog suffers from excessive amounts of waxy build-up in the ears then your vet is likely to recommend a cleaning regime. We have some ear cleaners available here in our shop.
• Manage underlying skin allergies. There are various treatment options now available – have a chat to your vet about which is most suitable for your dog.