Otitis Externa in Dogs: Causes, Symptoms and Care

What is Otitis Externa?

Otitis externa is inflammation of the external ear canal in dogs, often affecting the ear pinna (outer ear flap). It is the most frequent ear disorder seen in dogs, causing discomfort and sometimes recurrent issues. Unlike otitis media and otitis interna, which affect the middle and inner ear respectively, otitis externa primarily involves the outer ear canal and is usually the initial stage of ear infections.

Causes of Otitis Externa in Dogs

Several factors can lead to otitis externa, including:

• Bacterial infections – common secondary infections that thrive in an inflamed environment.
• Fungal infections – often caused by yeast overgrowth, particularly Malassezia species.
• Ear mites (otodectes cynotis) – microscopic parasites causing intense irritation.
• Foreign bodies – grass seeds or debris lodged in the ear canal.
• Tumours – such as squamous cell carcinomas or benign polyps.
• Poor ear anatomy – breeds with long, floppy ears or hairy ear canals are more prone due to reduced air circulation.
• Underlying medical conditions – allergies (food or environmental), metabolic issues like hypothyroidism, or inherited diseases like dermatomyositis in Collies and Shetland Sheepdogs.

Chronic irritation or inflammation can lead to increased wax production and a higher risk of secondary infections. Identifying and managing any underlying causes is crucial for successful treatment and prevention of recurrence.

Which Dogs are Most at Risk?

• Dogs with allergies to food or environmental factors.
• Breeds with long floppy ears such as spaniels and retrievers.
• Dogs with very hairy ear canals.
• Specific breeds with predispositions: Shetland Sheepdogs puppies and Collie puppies may be prone to dermatomyositis.
• Shar Pei puppies and West Highland White Terrier puppies may develop seborrhoea, increasing risk.

Recognising Symptoms

Common signs of otitis externa include:

• Ear scratching or rubbing
• Head shaking, which may cause an aural haematoma (ear swelling from blood accumulation)
• Redness and swelling of the ear canal
• Waxy or coloured discharge with possible unpleasant odour
• Itching or irritation causing distress
• Lethargy or irritability due to discomfort

If these symptoms are present, prompt veterinary assessment is essential to avoid progression and complications such as damage to the ear drum or deafness.

Diagnosing Otitis Externa

A vet will perform a detailed examination including:

• Otoscopic inspection to visualise the ear canal and check for foreign bodies or tumours.
• Taking samples (swabs or smears) to identify bacteria, yeasts, or parasites under the microscope.
• Additional tests such as blood work or allergy testing if an underlying cause like food allergy or hypothyroidism is suspected.

It's crucial not to clean the ear excessively before diagnosis as this might hinder accurate test results and aggravate the condition.

Effective Treatment Options

Treatment depends on identifying and addressing the root cause(s). Common therapies include:

• Topical and/or oral antibiotics for bacterial infections.
• Antifungal medications to control yeast infections.
• Anti-inflammatory drugs to reduce pain and swelling.
• Ear cleaning solutions recommended by your vet to safely clear debris.
• Immunotherapy or allergy management if allergies are involved.
• Nutritional therapy especially if food allergies contribute to the condition.

Many dogs benefit from a holistic approach combining medication, ear care routines, and allergy management to prevent recurrence.

Nutrition and Dietary Management

Supporting your dog's recovery with the right nutrition is essential, particularly if food allergies are suspected. Veterinary recommended hypoallergenic or novel protein diets exclude common allergens like beef, dairy, and gluten and use unique protein and carbohydrate sources dog has not previously eaten.

Hydrolysed protein diets may be prescribed for food trials — these contain proteins broken down into tiny fractions less likely to provoke immune responses. These diets can sometimes be less palatable or more costly, so your vet will guide you through options.

Practical Tips for Owners

1. Always follow your vet’s instructions on ear cleaning and medication application. Ask for a demonstration if unsure.
2. Review all treats and extras for hidden allergens during dietary trials.
3. Discourage your dog from scratching or rubbing ears to prevent further injury.
4. Schedule regular veterinary check-ups, especially if your dog has a history of ear problems or allergies.
5. Maintain good ear hygiene and drying after swimming or baths.

Conclusion

Otitis externa is a common but complex condition that can cause significant discomfort in dogs. Early veterinary diagnosis, appropriate treatment tailored to the underlying cause, and ongoing management including nutritional support are key to successful outcomes. Responsible pet ownership includes monitoring ear health and seeking professional advice promptly to prevent chronic or progressive ear disease.