What is Otitis Externa in Dogs?
Otitis externa is the inflammation of the outer ear and ear canal. It is the most common ear infection in dogs.
In otitis externa, the middle ear is not involved and the ear flaps (pinna) may or may not be involved.
Otitis externa can be acute – inflammation that occurs suddenly, or chronic – inflammation that has continued for weeks or months.
External ear infection can affect both the ears or one ear of the dog.
What are the Signs of Otitis Externa in Dogs?
The signs of otitis externa in dogs is identical to signs of ear infection in dogs discussed in the previous blog.
The signs of otitis externa in dogs include –
- Head shaking
- Strange smell from the ears
- Swelling
- Redness
- Ulceration
- Presence of excessive sticky substances on the ears
- Inflammation of the gland that produces earwax
What Causes Otitis Externa in Dogs?
The classification of the causes of otitis externa is divided into “causes” and “factors”. The causes include diseases or infectious agents, while the factors contribute or promote the inflammation.
The causes of otitis externa in dogs is classified as primary, and secondary. There can be perpetuating factors and predisposing factors that increase the risk of dogs to develop the infection and inflammation in the first place.
Primary causes of Otitis Externa in Dogs
The primary causes of otitis externa in dogs –
- Allergy
- Parasites
- Fungi
- Viruses
- Autoimmune diseases
- Hormonal disorders (hypothyroidism, hyperadrenocorticism)
- Foreign bodies
- Disorders of the glands in the ears
Secondary Causes of Otitis Externa in Dogs
Secondary causes of otitis externa in dogs create the inflammation in an already “abnormal” ear. These are commonly recurrent infections.
The secondary causes of otitis externa in dogs include –
- Bacteria
- Yeast (malassezia)
- Reactions to medication
- Abrasions from overcleaning
Perpetuating Factors of Otitis Externa in Dogs
The perpetuating factors are present due to ear inflammation and they can be quite severe in the chronic cases of otitis externa.
The perpetuating factors of otitis externa include –
- Epithelial changes
- Changes in the ear canal
- Injury to the eardrum (tympanum)
- Swelling (hyperplasia) of the gland(s)
- Middle ear disease (otitis media)
Predisposing Factors of Otitis Externa in Dogs
Predisposing factors make some dogs more susceptible to developing otitis externa. These include –
- The shape, size and hair density of their ears
- Environmental factors such as moisture (swimming)
- Primary otitis media or middle ear infection
- Obstruction in the ear or ear canal
- Systemic diseases
- Side effects of other treatments
Diagnosis of Otitis Externa in Dogs
The diagnosis of otitis externa is ONLY made by the veterinarian based on the dog’s medical history, physical examination (otoscopy) and cytology.
Some breeds are more predisposed to otitis externa due to their allergy profiles, for example, Golden Retriever, Labrador Retriever, Poodle, German Shepherd, Cocker Spaniel and terrier breeds. Young dogs may be more commonly affected.
The clinical signs combined with complete physical examination contribute to the conclusive diagnosis of otitis externa in dogs.
During the otoscopic examination, the dog can be sedated depending on the pain and discomfort they are experiencing. Sedation and treatment with corticosteroids can make the otoscopic examination less painful for your pet.
Cytologic evaluation involves taking samples from the ears using a swab and examining the sample on slides using advanced microscopy. It can help the veterinarian determine whether the sample has bacteria, fungi, yeast, parasites or other types of cells present in the infected ear.
In case, the veterinarian cannot get a clear view of the eardrum due to excess swelling and discharge, they can recommend an X-ray.
What’s the Treatment for Otitis Externa in Dogs?
The treatment of ear infection in dogs should ONLY be prescribed by a veterinarian. The ideal treatment depends upon –
- The underlying causes of otitis externa
- The selection of medicines based on your dog’s medical history, health and cytology reports
Most dogs will require pain management and medication for itching. Your veterinarian will recommend these medicines depending on your dog’s current health, weight and age.
Topical antibiotics and antimicrobial drops are the most commonly prescribed medicines. They are most effective in the treatment of otitis externa in dogs.
Ear cleaning and flushing may be prescribed for 2 to 3 days per week until the odour, swelling and discharge subside.
Oral antimicrobial medicines may also be recommended by the veterinarian. However, they are in no way replacements for the topical ear drops and ear cleanings.
Do not use antiseptic or antimicrobial powders on your dog’s ears. They can solidify with the discharge and worsen the irritation in their ear canals.
The duration of the treatment depends upon how badly the ear(s) is affected and also the type of infection leading up to otitis externa. Do not stop the treatment once the ears begin to “look better”. Speak to the vet once the condition of your dog’s ears begin to improve.
Preventing Otitis Externa in Dogs
According to experts around the globe, prevention is the best treatment for chronic ear infection!
- Avoid the food and environmental triggers of your dog’s allergy.
- Clean their ears at least weekly.
- Always dry their ears completely after baths and swims.
- Trim the extra hair around their ears if they trap water.
- Give them parasite preventives (spot-on, Bravecto or Simparica) at the correct intervals.
Visit the veterinarian for preventive check-up if your dog scratches their ears or you see nail marks on/in their ears.