Ear infections — diagnosis and treatment (otoscopy)

What it involves

Otitis externa is inflammation of the ear canal, which in a dog is long and bent, so it easily collects moisture and discharge. It is usually accompanied by an overgrowth of yeasts or bacteria, but these are rarely the primary cause — more often the background is an allergy, a foreign body, parasites, a polyp or the shape of the ear. Treating the infection alone without finding the cause ends in a relapse.

Diagnosis is based on otoscopy — examination of the canal and eardrum — and cytology of the discharge, which we assess under the microscope straight away. This lets us choose the right medication and check whether the eardrum is intact, which matters for the safety of ear drops.

In chronic, painful or recurrent infections we perform video-otoscopy under sedation: a detailed look at the canal on a screen, ear flushing under direct vision, removal of a foreign body or taking a biopsy from a polyp. We assess the middle ear on an X-ray.

When it is used

Book a visit when your dog or cat shakes its head, scratches its ear, tilts its head, there is discharge or a smell from the ear, and the pinna is red and painful. If there is severe pain, a sudden head tilt with balance problems, or a drooping eyelid, come the same day.

Infections recurring more often than 2–3 times a year, lasting more than a month, or affecting both ears need extended diagnosis for allergy and an assessment of the middle ear, not another course of drops.

Indications: symptoms that should prompt a visit

• Your dog shakes its head and scratches its ear until a haematoma appears on the pinna.
• A brown, foul-smelling discharge comes from the ear, and the skin of the canal is red and thickened.
• Your cat has a dry, black, “coffee-ground” discharge in its ears and scratches intensely.
• After a swim in a lake, your dog started tilting its head and yelps when you touch the ear.
• The ear becomes inflamed again every few weeks after a course of drops ends.
• The animal has a permanent head tilt, walks in circles or has a drooping eyelid on one side.
• Your dog has begun to hear less well and does not respond when called.

Conditions for which we use it in particular

Diagnostics beforehand

At the visit we examine the ear with an otoscope and take a swab for cytology, which we assess under the microscope on site — this determines the choice of medication. If ear mites are suspected we examine the discharge for parasites. We send a bacterial culture with an antibiogram when rod-shaped bacteria are seen on cytology or the inflammation does not respond to treatment.

Where pain makes examination impossible, discharge fills the canal or damage to the eardrum is suspected, we plan video-otoscopy under sedation, together with a pre-anaesthetic assessment (examination, blood tests). We assess the middle ear on a skull X-ray in special projections; with relapses we look for the primary cause — allergy diagnosis, hormone tests.

How it proceeds

Aftercare

Give the drops for exactly as long as advised, even if the signs disappear after a few days — stopping too early is the main cause of relapses. Clean the ears with the preparation according to the instructions, not with cotton buds. With allergy, and in dogs with floppy ears or dogs that swim, regular preventive cleaning remains a permanent routine.

At the check-up we repeat otoscopy and cytology; we stop medication only when the ear is clean under the microscope. Call earlier if a head tilt, balance problems, a drooping eyelid, increased pain or an aural haematoma appears.

Frequently asked questions