Dog Ear Infection Signs: Smell, Discharge, Redness and Head Shaking

A dog repeatedly shaking its head, scratching an ear, developing a strong ear smell or showing redness and discharge may have an unhealthy ear that needs veterinary assessment. These are among the common dog ear infection signs, but they do not reveal the exact cause.

Outer-ear inflammation can be associated with bacteria, yeast, allergies, parasites, foreign material and other problems. A veterinarian may need to look inside the canal and examine a sample of the discharge before determining what treatment is appropriate. Colour or smell alone should never be used to decide whether an ear problem is bacterial, fungal or caused by mites.

Direct Answer

Common signs of an unhealthy dog ear include repeated head shaking, scratching, redness, swelling, pain, strong odour and abnormal wax or discharge. One or both ears may be affected. Because different ear problems can produce similar symptoms, the appearance or smell cannot identify the cause; veterinary examination and ear cytology may be needed.

What a Healthy Dog Ear Generally Looks Like

A healthy ear generally should not be markedly red, swollen, painful, strongly odorous or filled with abnormal discharge. Some normal wax can be present, and individual dogs differ in how much visible wax they naturally produce.

Cornell recommends watching for changes such as redness, increased wax or discharge, odour, itching, head shaking and discomfort when the ear is touched. These changes are more useful than trying to compare every dog’s ear with one universal idea of “normal.”

A dog’s usual baseline matters. An ear that suddenly develops much more wax, a new smell or persistent redness deserves attention even if another dog naturally has a slightly different-looking ear.

Head Shaking

Repeated head shaking is one of the classic signs of ear discomfort.

Dogs with otitis externa commonly shake their heads because the ear canal is itchy, painful or contains abnormal debris or fluid. However, head shaking does not prove that an infection is present; parasites, foreign material and other sources of ear inflammation can cause similar behaviour.

A single shake after waking or getting wet is different from frequent, forceful shaking that continues throughout the day.

If your dog keeps shaking its head, especially with redness, discharge, odour or pain, arrange a veterinary examination.

Ear Scratching

A dog scratching its ears repeatedly may be responding to itching, inflammation or pain.

Scratching is commonly reported with otitis externa but also occurs with ear mites and allergic ear disease. Cornell specifically notes that dogs with allergic ear disease may show some of the same symptoms even when infection is not present.

Look at the skin around the ear as well. Repeated scratching can cause secondary skin damage around the ear flap.

If your dog has itchiness elsewhere on the body too, Pawnium’s Dog Itchy Skin guide can provide useful related information without assuming the ear problem and skin problem have the same cause.

Redness

Red dog ears can indicate inflammation, particularly when the redness is new or appears inside the ear canal.

Merck lists erythema, or redness, among common findings in otitis externa. VCA similarly notes that affected ears frequently become red and inflamed.

Redness alone does not determine whether bacteria, yeast, allergies, mites or irritation are responsible.

Persistent redness is a reason to have the ear examined rather than repeatedly treating it with home remedies.

Swelling

Inflammation can make the ear canal or surrounding tissues appear swollen.

Merck includes oedema and swelling among recognised signs of external-ear inflammation. Chronic inflammation can also cause structural changes within the canal.

Swelling may make the ear opening look narrower than usual.

Marked swelling, substantial pain or an ear that cannot be examined comfortably should be assessed by a veterinarian rather than deeply cleaned at home.

Pain

Ear problems can be painful even when a dog does not cry.

Signs of discomfort may include:

• pulling away when the ear is approached
• reluctance to have the head touched
• repeated head shaking
• scratching
• rubbing the ear
• unusual irritability when the ear is handled

Merck and VCA both describe pain as a common feature of otitis externa. Painful ears may require sedation or anaesthesia so a veterinarian can safely examine and clean the canal without causing unnecessary distress.

If touching the ear clearly hurts your dog, stop examining it.

Strong Odour

If a dog ear smells bad, the odour is worth recording and discussing with your veterinarian.

Malodour is a recognised sign of otitis externa, and VCA notes that affected ears may develop an unpleasant smell.

What an owner should not do is use the smell to diagnose the organism involved.

A particular odour cannot reliably tell you that the ear contains yeast rather than bacteria. Ear discharge may need microscopic examination to identify organisms and guide treatment.

Brown Discharge

Brown discharge in a dog’s ear may be wax, inflammatory debris or material associated with several different ear problems.

Dark or brown material is sometimes discussed in relation to yeast or parasites, but Merck specifically cautions that dark discharge can also occur with bacterial or mixed infections. Appearance therefore cannot identify the cause.

A brown discharge accompanied by persistent scratching, head shaking, redness or odour should be examined by a veterinarian.

Do not diagnose ear mites or yeast from brown material alone.

Yellow Discharge

Yellow discharge from a dog’s ear is abnormal, particularly when there is a large amount or it occurs with odour, pain or redness.

VCA notes that yellowish discharge can occur with canine external-ear infections. However, the colour does not reveal which organism is present or which medication is appropriate.

A veterinarian may examine ear discharge microscopically through cytology before selecting treatment.

Do not choose antibiotic or antifungal drops based only on the discharge colour.

Dark Debris

Dark ear debris can occur with several different problems.

Possible explanations include:

• wax
• inflammatory debris
• ear mites
• yeast
• bacteria
• mixed ear disease

VCA notes that black discharge can occur with both ear infections and ear mites, while Merck explains that dark material is not specific enough to identify the cause.

This is why “dark debris equals mites” and “brown debris equals yeast” are not reliable rules.

Crusting

Chronic irritation and inflammation can result in crusty or scaly skin around the ear or within accessible parts of the ear flap.

VCA notes that chronic cases may develop crusting, while Merck lists scaly skin among signs associated with otitis externa.

Crusting can also develop after repeated scratching and self-trauma.

Do not peel crusts aggressively or insert tools into the canal.

Thickened Ear Canal

Repeated or long-lasting inflammation can change the structure of the ear canal.

VCA notes that chronic ear disease can cause the canal to become thickened and narrowed. Merck also describes chronic structural changes and swelling that may make examination and treatment more difficult.

A visibly narrowed or thickened ear canal is not a problem to manage with routine home cleaning alone.

Chronic structural change increases the importance of veterinary investigation into the factors causing the ear disease to keep returning.

Hair Loss Around the Ear

Hair around the ear can become thin or damaged when a dog repeatedly scratches or rubs the area.

This does not identify the underlying cause. Ear inflammation, skin disease or repeated self-trauma can all contribute to changes around the ear flap. Merck notes that veterinarians inspect the ear flaps and nearby skin for evidence of self-trauma and other skin changes during evaluation.

If hair loss also appears on the paws, face or other areas, consider linking readers to Pawnium’s Dog Itchy Skin and Dog Paw Licking guides.

One Ear Versus Both Ears

Ear disease may affect one ear or both.

Merck notes that otitis externa can occur unilaterally or bilaterally and may be sudden or chronic.

Which ears are affected is worth recording, but it does not diagnose the cause.

Persistent one-sided disease can sometimes prompt veterinarians to investigate for problems such as foreign material or abnormal tissue, while recurring problems in both ears may raise different questions about underlying factors. Merck notes that additional investigation may be appropriate in chronic or unilateral cases.

Floppy-Ear Considerations

Dogs with large, floppy or heavily haired ears may be more predisposed to external-ear problems because ear conformation can affect airflow and the environment within the canal.

VCA identifies breeds with large, floppy or hairy ears as more prone to ear infections, while Merck notes that the shape of the ear flap and canal can influence susceptibility.

That does not mean every floppy-eared dog will develop infections.

Regular observation is more useful than assuming breed or ear shape determines the diagnosis.

Dogs That Swim

Swimming and bathing can leave moisture in the ear canal.

VCA notes that trapped moisture combined with the warm environment inside the ear can contribute to conditions that support microbial overgrowth.

Dogs that frequently swim may therefore need a veterinarian-approved preventive ear-care routine.

For routine preventive cleaning after swimming or bathing, link readers to Pawnium’s How to Clean Dog Ears Safely article rather than giving a second full cleaning tutorial here.

Do not begin deep cleaning a painful, red or severely inflamed ear simply because the dog recently went swimming.

Allergy-Related Ear Problems

Allergies are an important underlying factor in recurrent ear disease.

Merck lists allergies among possible causes of otitis externa, and VCA notes that underlying allergies are common in dogs with chronic or recurring ear problems.

An important distinction is that allergic inflammation can cause itching, redness and other ear symptoms even when an active infection is not present. Cornell specifically notes this overlap.

That is another reason owners should not diagnose an infection based solely on symptoms.

If your dog also has recurring body itching or paw licking, useful internal links include:

• Dog Itchy Skin
• Dog Paw Licking
• Consolidated Itchy-Skin Shampoo Guide

Ear Mites and Other Possible Causes

Ear mites can cause:

• scratching
• head shaking
• dark debris
• irritation

However, these symptoms overlap with other ear disorders.

VCA explains that the signs of ear mites can look very similar to external-ear infection and notes that mites are more common in puppies, although adult dogs can also be affected.

A veterinarian may inspect material microscopically or examine the ear with an otoscope to distinguish parasites from bacteria, yeast and other causes.

Do not diagnose mites simply because dark debris is present.

Foreign Material

Grass awns, plant material and other foreign objects can enter the ear canal and cause sudden irritation.

Merck lists objects lodged in the canal among possible causes of otitis externa. Otoscopic examination allows a veterinarian to look for foreign bodies, impacted debris, parasites and eardrum abnormalities.

A foreign body may be especially worth considering when ear discomfort starts abruptly, but an owner should not insert tweezers, cotton swabs or other tools deep into the canal.

Deep objects should be removed under appropriate veterinary visualisation and restraint.

Chronic Ear Problems

Repeated infections or inflammation should prompt a search for the underlying reason rather than simply treating each flare as an isolated event.

Potential contributing factors include:

• allergies
• parasites
• ear anatomy
• foreign material
• chronic inflammation
• middle-ear disease
• microbial overgrowth

Merck emphasises that all contributing factors need to be identified because ear problems can continue to return if the underlying cause remains untreated.

Chronic disease can also lead to a thickened or narrowed canal, making future treatment more difficult.

Balance Changes

Loss of balance is different from the usual signs of uncomplicated outer-ear inflammation.

Middle- or inner-ear disease can affect structures involved in balance. Merck notes that inner-ear involvement can produce vestibular abnormalities, while VCA lists leaning, falling, circling and difficulty walking among possible signs of inner-ear disease.

If your dog suddenly cannot balance normally, contact a veterinarian promptly.

Do not assume the dog is simply dizzy because it has been scratching an ear.

Head Tilt

A persistent head tilt can occur with deeper ear disease or other neurological/vestibular problems.

Merck describes an ipsilateral head tilt as a possible sign of otitis interna, while VCA also lists head tilt among signs of inner-ear infection.

Head tilt becomes more concerning when accompanied by:

• loss of balance
• falling
• circling
• rapid abnormal eye movements
• vomiting or nausea
• facial weakness

These signs require veterinary assessment rather than routine home ear cleaning.

Why Owners Should Not Diagnose Infection Type

A dog’s symptoms cannot reliably tell you whether bacteria, yeast, mites or another problem is responsible.

Smell is not a diagnostic test.

Brown discharge is not a diagnostic test.

Yellow discharge is not a diagnostic test.

Dark debris is not a diagnostic test.

Veterinarians may use:

• history
• physical examination
• otoscopic examination
• ear cytology
• additional testing in chronic or complicated cases

Merck identifies otoscopy and cytology as key parts of diagnosing otitis externa. A swab of discharge can be examined microscopically for bacteria, yeast or parasites.

Treatment should therefore be selected based on the actual diagnosis rather than on an internet description of the discharge.

What Owners Should Photograph or Record

A short symptom record can make the veterinary history much clearer.

Record:

1. Which ear is affected
2. When the problem started
3. Whether symptoms began suddenly or gradually
4. How often your dog shakes its head
5. How often the ear is scratched
6. Redness
7. Swelling
8. Visible wax or debris
9. Discharge colour and general appearance
10. Odour
11. Pain when the ear is approached
12. Any recent swimming or bathing
13. Known allergy history
14. Previous ear problems
15. Current ear products or medications
16. Balance changes
17. Head tilt
18. Other skin itching or paw licking

Take a clear photo of visible discharge or redness if your dog allows this without discomfort.

Do not repeatedly manipulate a painful ear just to get a better photograph.

What Not to Put Into an Unhealthy Ear

Do not experiment with household remedies in a red, painful, swollen or discharging ear.

Avoid putting the following into an unhealthy ear unless a veterinarian specifically instructs otherwise:

• vinegar mixtures
• hydrogen peroxide
• rubbing alcohol
• essential oils
• leftover prescription ear drops
• another pet’s medication
• unapproved wax-removal products

Merck specifically advises avoiding irritating home remedies such as vinegar mixtures because they can worsen swelling and secretions in an inflamed canal.

Cornell advises avoiding ear-cleaning products containing alcohol or hydrogen peroxide because they can irritate the ear, particularly when the canal is already inflamed.

Essential oils should not be improvised as ear treatments. Cornell identifies tea tree oil, for example, as toxic to dogs and cats when used improperly.

Also avoid deep or vigorous cleaning when an ear is painful or severely inflamed. Cornell advises stopping home cleaning if the dog appears painful and notes that severe infections may initially need veterinary treatment before home cleaning can be tolerated.

Routine ear-cleaning technique belongs in Pawnium’s separate How to Clean Dog Ears Safely guide.

When Veterinary Care Is Needed

Arrange veterinary assessment when your dog has:

• persistent head shaking
• repeated ear scratching
• redness
• swelling
• obvious pain
• a strong or new ear odour
• brown, yellow, black or otherwise abnormal discharge
• substantially increased wax
• crusting
• a thickened or narrowed-looking canal
• repeated ear problems
• symptoms that keep returning after treatment
• a possible foreign object
• ear symptoms associated with significant skin allergies

Veterinary examination may include otoscopy and cytology so the ear canal, eardrum and discharge can be properly evaluated.

Do not delay evaluation simply because your dog is still eating and behaving normally otherwise. Painful ear disease can worsen, and treatment choice depends on what is actually happening within the canal.

Urgent Warning Signs

Seek Prompt or Urgent Veterinary Care If…

Seek prompt veterinary assessment if an ear problem is accompanied by:

• sudden loss of balance
• falling or rolling
• difficulty walking normally
• persistent head tilt
• circling
• rapid involuntary eye movements
• facial drooping or weakness
• inability to blink normally
• severe pain
• marked swelling
• significant bleeding
• sudden neurological abnormalities

Middle- and inner-ear disease can affect structures involved in balance and nerves controlling parts of the face. Merck and VCA describe head tilt, loss of balance, facial nerve problems and vestibular abnormalities among signs of deeper ear involvement.

Do not attempt deep cleaning when neurological or balance signs are present.

FAQs

How can I tell if my dog has an ear infection?

Common signs include repeated head shaking, scratching, redness, swelling, pain, odour and abnormal discharge. However, these symptoms can also occur with allergies, ear mites and foreign material, so a veterinarian may need to examine the ear before confirming the cause.

Does brown ear discharge mean my dog has yeast?

No. Brown or dark discharge cannot diagnose yeast. Merck notes that dark discharge may occur with yeast, parasites, bacterial infection or mixed problems. Cytology is more useful for identifying what is present.

Why does my dog’s ear smell bad?

A strong unpleasant odour can occur with ear inflammation or infection, but the smell does not identify whether bacteria or yeast are responsible. Veterinary examination and cytology may be needed.

Can I put hydrogen peroxide in my dog’s infected ear?

Do not use hydrogen peroxide in an inflamed ear unless your veterinarian specifically directs you to. Cornell and VCA note that peroxide-containing cleaners can irritate inflamed ear canals.

Should I clean my dog’s ear if it is painful?

Do not force deep cleaning of a painful or severely inflamed ear. Cornell advises stopping if cleaning causes pain, and veterinary cleaning may be delayed or performed with appropriate medical management when inflammation is severe.

Is a head tilt an emergency with an ear problem?

A persistent head tilt, especially with loss of balance, circling, falling, vomiting or abnormal eye movements, can indicate deeper ear or vestibular involvement and needs prompt veterinary assessment.