Otitis externa (ear infection)

Symptoms an owner can spot at home

• Head shaking or tilting
• Scratching at the ear or rubbing the head along furniture
• Visible redness or swelling at the ear opening
• Discharge, yellow, brown, or black
• Strong, sour, or yeasty odor from the ear
• Pain when the ear is touched

When to see a vet

• Any first-time ear infection, owners cannot reliably tell yeast from bacterial from mites at home, and the wrong treatment makes it worse
• Recurrent infections in the same ear or on both sides, points to an unaddressed underlying cause
• Sudden head tilt, loss of balance, or facial drooping, these are middle/inner ear emergencies
• Ruptured eardrum (vet may identify this), drug choice has to change

What it is

Otitis externa is inflammation of the ear canal up to (but not through) the eardrum. Bacteria and yeast that normally live on the skin overgrow when the canal microenvironment is disturbed, increased humidity, allergic skin disease, anatomical obstruction, foreign material, or a parasite shift the balance and an infection takes hold.

Modern veterinary dermatology frames otitis with the PSPP system: Primary cause (e.g. allergy, foreign body), Secondary infection (bacteria, yeast), Predisposing factors (pendulous ears, swimming, narrow canals), and Perpetuating factors (chronic changes to the canal that prevent resolution). Treating only the secondary infection guarantees recurrence.

How vets diagnose it

A complete ear exam includes otoscopy to visualize the canal and eardrum, cytology (microscope exam of a swab) to identify what is overgrowing, and, for recurrent or non-responsive cases, culture and sensitivity. Sedation may be needed for painful ears or deep examination. Identifying the primary cause is the goal, not just treating the visible discharge.

Treatment overview

This is editorial overview, not a treatment plan, your vet builds the plan from cytology and the patient's history. Acute uncomplicated cases are typically managed with a thorough cleaning, an appropriate topical preparation matched to the organism, and pain/anti-inflammatory support. Chronic or recurrent cases require working up the primary cause: food trial for adverse food reaction, environmental allergy workup, removal of foreign material, or surgery for end-stage canal disease.

Do not pour at-home solutions, hydrogen peroxide, vinegar, or human earwax remedies into an ear that may have a ruptured eardrum, that can cause middle-ear damage.

What owners can do

• Dry ears after baths and swimming, moisture is the most common predisposing factor.
• Use a vet-recommended ear cleaner on the schedule your vet specifies. Cleaning a healthy ear too often disrupts the microbiome.
• Watch food-allergic and atopic dogs closely, chronic otitis is often the first sign of the underlying skin disease.
• Do not insert cotton swabs into the canal. Wipe what you can see; let cleaner flush the rest.