Ear Infections (Otitis Externa) in Dogs

Otitis externa is inflammation of the external ear canal distal to the tympanic membrane; the ear pinna may or may not be involved. It is one of the most common reasons for small animals (especially dogs) to be presented to the veterinarian. Otitis externa may be acute or chronic, and unilateral or bilateral.

Acute and uncomplicated otitis externa can often be treated successfully, but chronic or recurrent otitis externa is more challenging. Typically, underlying primary factors as well as predisposing and perpetuating factors are at play, including secondary otic infection. Repeated bouts of inflammation and infection can cause secondary changes in the ear canal that can ultimately lead to further lack of success in treating otitis, and possible end-stage ear disease.

Some breeds, particularly those with large, floppy or hairy ears like Cocker Spaniels, Miniature Poodles, or Old English Sheepdogs, appear to be more prone to ear infections, but ear infections may occur in any breed.

Causes of Otitis Externa in Dogs

• Dogs with long floppy ears or thick hair within the ear may be more prone to this condition
• Allergies to some environmental irritants such as mold, dust and some foods
• Bacterial or yeast infections
• Tumor
• Infection through your dog breaking the skin during scratching their ears
• Flea bites (some dogs are hypersensitive to bites from fleas )
• Excess water in the ears, especially if your dog swims a lot
• Seeds or other objects trapped in the external ear
• Ear mite infections

Symptoms of Otitis Externa in Dogs

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.

Treatment of Otitis Externa in Dogs

Treatment for otitis externa and otitis media usually involves outpatient care, unless the inflammation or infection has moved into the inner ear. In most cases of otitis externa, a topical therapy following a complete cleansing of the external ear is an effective resolution to the problem. The topical therapy may consist of antibacterial, corticosteroid, anti-yeast, and antiseptic drops. In severe cases of otitis externa and otitis media — where the presence of infectious organisms has been confirmed — oral antibiotics and antifungals may be prescribed. Corticosteroids may also be used to reduce the animal’s pain and swelling.

Prevention and Maintenance

Owners should be shown how to properly clean the ears. The frequency of cleaning usually decreases over time from daily to once or twice weekly as a preventive maintenance procedure. The ear canals should be kept dry and well ventilated. Using topical astringents in dogs that swim frequently and preventing water from entering the ear canals during bathing should minimize maceration of the ear canal. Chronic maceration impairs the barrier function of the skin, which predisposes to opportunistic infection. Preventive otic astringents may decrease the frequency of bacterial or fungal infections in moist ear canals.