How to tell if dog has ear infection?

Ear problems are one of the things I tell every dog owner to watch for because they often start small and can rapidly become painful or chronic. Noticing an ear problem early usually means a simpler, quicker fix and a better chance of preserving your dog’s comfort and hearing long term.

Why spotting ear infections early protects your dog’s comfort and long-term health

Owners notice ear trouble for reasons that matter: a dog that stops playing, seems reluctant to have its head touched, or suddenly paws at an ear is sending a clear message. These are the scenarios that commonly lead people to ask whether their pet has an infection. Left unchecked, repeated or severe ear inflammation is likely linked to scarring, chronic pain and a higher risk of hearing loss later in life.

Certain breeds and ear types are more likely to develop problems. Dogs with long, floppy ears or narrow ear canals—Cocker Spaniels, Basset Hounds, many spaniels and some retrievers—tend to trap moisture and reduce air flow, which may encourage microbes to multiply. Breeds with very hairy ear canals, such as some poodles and terriers, also appear more prone. I typically see a mix of anatomy and lifestyle (for instance, dogs that swim a lot) in cases that recur.

Because ear pain changes behavior, it also affects the human–dog bond. A dog that suddenly shies away from grooming, retreats during play, or avoids interaction is communicating discomfort. Detecting an ear problem early relieves that discomfort sooner and prevents weeks or months of altered behavior.

At a glance: Is this an ear infection?

There’s no single home test that proves an infection, but a few hallmark signs often point strongly in that direction. If you see a combination of these, an infection is likely and a prompt veterinary exam is warranted.

• Head shaking or repeated ear scratching; persistent rubbing of the ear on furniture or the floor.
• An unpleasant or strong odor from the ear, or dark, yellow, brown, or greenish discharge.
• Visible redness, swelling or heat of the ear flap or entrance to the ear canal; your dog recoils or snaps when you touch the ear.

At home you can safely do a few simple checks to assess severity. Gently lift the ear flap and look into the entrance of the canal under good light; the canal should look pink and free of heavy discharge. Smell the area—an offensive, yeasty or putrid odor often suggests active infection. Watch your dog’s reaction when you gently press the base of the ear: if it flinches, whines or pulls away, that may indicate significant pain. If the ear is just a little red without smell, you might monitor for 24–48 hours; if there is heavy discharge, odor, intense pain, or neurologic signs such as tilt or loss of balance, seek veterinary attention the same day.

Inside the canine ear — structure, function, and why it matters for diagnosis

Understanding why infections happen is easier when you know the basics of the ear. The external ear includes the ear flap (pinna) and the vertical and horizontal ear canal; the canal leads to the eardrum, which separates the external canal from the middle and inner ear. Infections that start in the external canal are usually called otitis externa, while involvement behind the eardrum is otitis media or interna and is more serious.

Ears produce wax (cerumen) as part of normal cleaning and protection. Cerumen traps debris and contains substances that may help control microbes. With normal air flow and occasional grooming, the ear canal sheds and clears cerumen; when that balance shifts—because of moisture, anatomy or inflammation—wax can build up and create an environment where bacteria or yeast are likely to flourish.

The microbes commonly involved include bacteria and Malassezia yeast; in puppies and some adults, ear mites can be a primary cause. These organisms are often present at low levels and only proliferate when conditions favor them, so finding one of them on a swab may suggest an infection but doesn’t always explain why it started.

When infections take hold: common causes and high-risk situations

Ear infections are usually the result of an interaction between environment, anatomy and your dog’s skin health. Moisture exposure is a frequent trigger: dogs who swim frequently or who get water introduced into the ear during baths may be more likely to develop problems because dampness reduces natural defenses and promotes microbial growth.

Allergies are a common underlying driver. Dogs with atopic skin disease often have ongoing ear inflammation that is likely linked to allergic reactions; the inflamed skin is a poorer barrier and becomes an inviting place for microbes. If you notice seasonal or food-related itching alongside ear problems, allergies may be contributing.

Ear conformation matters. Floppy ears reduce air flow; hairy ear canals or narrow canals trap wax and moisture. These physical characteristics are likely linked to the breed predispositions you see clinically. Immune status, age and medications also play roles—older dogs or those on immune-suppressing drugs can be more vulnerable, and some antibiotics or steroid treatments may change microbial balance in the ear.

Warning signs that require prompt veterinary attention

Most ear infections can be managed well if caught early, but some signs indicate more serious disease and need urgent care. Severe, unrelenting pain, persistent head tilt, circling or loss of balance may suggest the infection has extended beyond the external canal into the middle or inner ear and possibly affected the nerves that control balance.

A thick, foul-smelling discharge, especially if blood is present, increases the likelihood of a ruptured eardrum or deeper infection. Facial swelling, drooping of facial muscles, fever or marked lethargy are signs that the problem may be systemic or that the ear disease is severe; these situations are best evaluated immediately by your veterinarian. Recurrent infections, even when mild, may suggest chronic disease such as severe allergy, a foreign body deep in the canal, or a mass—these are reasons to pursue a deeper diagnostic workup.

What to do right now if you suspect an ear infection

When you suspect an ear infection, the safest, most useful first step is careful observation and documentation. Take clear photos or short videos of the affected ear, note when the signs started, whether your dog has been swimming or bathed recently, and whether other signs of skin allergy or illness are present. This information helps your veterinarian make a quicker, more accurate assessment.

Avoid putting over-the-counter ear drops into the ear without veterinary guidance. Some products may sting, hide worsening signs, or be inappropriate if the eardrum is ruptured. If your vet advises a gentle external clean before the visit, use a soft cotton ball with a veterinary-formulated ear cleanser and wipe only the visible outer ear—never insert anything down into the canal.

If your dog is painful and reluctant to be handled, or if you see neurologic signs or blood, seek a veterinary exam the same day. When you go, bring your notes and any photos—these can substitute for the history a restless dog can’t provide and may show progression that helps the clinician decide on tests like cytology, culture, or imaging.

Everyday care and home habits that lower infection risk

Prevention focuses on reducing the conditions that let microbes overgrow. Drying ears thoroughly after swimming or baths is one of the simplest, most effective steps; gently towel dry and, if your veterinarian approves, use a drying solution designed for canine ears. Avoid forcing water down the canal when bathing; keep the ear flaps lifted and try to prevent a direct spray into the entrance.

Regular, brief ear checks let you spot early signs. How often to clean is individual: some dogs need only a very occasional wipe, while others with recurrent issues may need scheduled cleansing as part of an overall plan. Ask your vet to show you the recommended technique and frequency for your dog—overcleaning can be as disruptive as undercleaning.

Because allergies often drive chronic ear disease, managing allergic triggers is important. That may mean dietary trials, environmental control (reducing dust, pollen exposure), and working with your veterinarian on an allergy treatment plan. Training your dog to accept gentle handling of the ears and rewarding calm behavior makes at-home checks and cleanings easier and less stressful for both of you.

Safe, practical tools and products for ear cleaning and protection

The right tools make prevention practical and safe. Veterinary-formulated ear cleansers and drying solutions are designed for the canine ear and are safer choices than generic human products. Use soft cotton balls or microfiber towels to wipe the outer ear and avoid cotton swabs or pointed implements that easily push debris deeper or damage the eardrum.

Keep a small kit with a vet-approved cleaner, soft wipes, and favorite treats for conditioning your dog to accept ear handling. For documentation, consumer otoscopes and clip-on phone lenses can help you capture images to show your veterinarian; use these cautiously and stop if your dog shows pain. If a dog is anxious, consider calming wraps, pheromone sprays, or short-term behavioral aids recommended by your veterinarian so that exams and cleanings can be performed safely.

Sources, studies and expert guidance behind this advice

• Merck Veterinary Manual: “Otitis externa in dogs” – Merck Veterinary Manual (https://www.merckvetmanual.com/), section on otitis externa
• American Veterinary Medical Association: “Ear infections in dogs” owner guidance and clinical resources
• American College of Veterinary Dermatology: Canine Otitis Externa resources and position statements
• Mueller RS. “Otitis externa in dogs and cats.” Veterinary Dermatology. 2004;15(2):79–86.
• Greene CE. Infectious Diseases of the Dog and Cat. 4th ed. (textbook reference for infectious causes and general management)
• Your primary care veterinarian or a board-certified veterinary dermatologist for individualized diagnosis and treatment