Otitis Externa

What Is Otitis Externa?

Otitis externa refers to inflammation or infection of the external auditory canal—the narrow tunnel that connects the outer ear (pinna) to the eardrum. The condition can affect anyone but is especially common in swimmers, divers, people with skin condition (like eczema) and people that excessively manipulate their ears.

Two main types exist:

• Acute otitis externa: Symptoms lasting less than a few weeks, usually bacterial.

• Chronic otitis externa: Inflammation persisting beyond 3 months, or repeated ear infections, often due to skin disorders, fungal infection, or allergic irritation.

The hallmark feature is pain and tenderness when manipulating the outer ear, which helps distinguish it from middle-ear infections.

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Pathophysiology (How It Develops)

The ear canal’s skin is unique: it has very thin epidermis (most outer skin covering), minimal fat, and a protective layer of cerumen (earwax). Cerumen keeps the ear canal slightly acidic (pH ~6), repelling bacterial and fungal growth. It also repels water and traps debris. Skin wax is therefore a key element in the natural barrier of the ear. You can read more about ear wax and its management here.

Otitis externa develops when this natural defense is compromised by:

1. Moisture – prolonged wetness (from swimming, sweating, or humid air) causes skin maceration (sogginess) and changes in pH, favoring bacterial growth.

2. Trauma – inserting cotton swabs, fingernails, or earbuds can scratch the skin, creating entry points for infection.

3. Skin conditions – eczema, psoriasis, or seborrheic dermatitis damage the skin barrier.

4. Absence of protective cerumen – over-cleaning or chronic drainage removes wax and exposes raw skin.

Once bacteria enter, they proliferate in the moist environment, leading to inflammation, swelling, and discharge.

In advanced cases, inflammation can spread to the cartilage and soft tissue surrounding the canal (causing cellulitis or chondritis). Rarely, it can spread to the bone in people with weakened immune system or diabetes, leading to osteomyelitis (also called "malignant otitis externa"). This condition is much more serious and requires urgent attention. You can read more about the complications of otitis externa towards the end of this article.

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Microbiology: The Germs Behind the Infection

Bacterial Causes (90% of cases):

• Pseudomonas aeruginosa: thrives in wet environments; produces a characteristic greenish, gasy-smelling discharge.

• Staphylococcus aureus: common skin bacterium; causes more localized, pustular infections.

• Mixed bacterial infections are frequent in chronic cases.

Fungal Causes (Otomycosis):

• Occur after prolonged antibiotic drop use or in chronically wet ears.

• Aspergillus niger – produces a black or gray “powdery” discharge.

• Candida albicans – causes white, fluffy debris (wet paper towel consistency) and intense itching.

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Risk Factors : Who Gets Otitis Externa?

• Frequent swimming or diving (“swimmer’s ear”).

• Excessive ear cleaning or scratching.

• Hearing aids, earplugs, or earbuds (trap heat and moisture).

• Underlying skin diseases (eczema, seborrheic dermatitis).

• Use of hair sprays, dyes, or shampoos irritating the canal skin.

• Chronic middle ear discharge leaking through a perforated eardrum.

• Diabetes mellitus, untreated HIV, chemotherapy, or other conditions which reduce immune response.

• Warm and humid environments, especially during summer months.

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Clinical Presentation

Symptoms can range from mild itching to severe pain and swelling.

• Ear pain (otalgia): sharp or throbbing, worse with jaw movement or ear manipulation.

• Itching or fullness: often the earliest symptom.

• Discharge (otorrhea): thin and watery at first, then thick or purulent (pus-like).

• Temporary hearing loss: caused by canal swelling or debris blockage.

• Tenderness: pain when pressing the tragus or pulling the pinna outward.

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Medical Work-Up 

History

A thorough medical history helps identify contributing factors:

• Recent water exposure or swimming.
• Ear cleaning habits or device use.
• Chronic skin problems.
• Presence of diabetes or immune suppression.
• Previous antibiotic ear-drop use.

Physical Examination

During the physical exam, the goal is to assess the severity, extent, and type of inflammation and to rule out deeper or adjacent infections. The following findings are typical in otitis externa:

External Ear (Pinna)

• • Tenderness: pulling on the pinna or pressing on the tragus (the small cartilage in front of the ear canal) triggers significant pain—this is a hallmark sign of otitis externa.

  • Swelling or redness: may extend slightly beyond the ear canal, but the pinna itself is usually only mildly affected unless there is secondary cellulitis.

Ear Canal

• • Redness and swelling: the canal skin appears erythematous (red) and thickened.

  • Moist debris or discharge: can be watery, purulent (pus-like), or thick depending on the stage of infection.

  • Crusting or fungal debris: fluffy white, black, or gray material may indicate fungal otitis externa.

  • Narrowing of the canal: in moderate to severe cases, swelling may almost completely close off the canal, limiting visibility.

  • Painful otoscopy: gentle insertion of the otoscope often elicits sharp pain.

  • Intact eardrum: the tympanic membrane (eardrum) usually looks normal but may be hard to visualize because of swelling or debris. If perforated, this suggests another underlying condition, such as chronic otitis media.

Regional Findings

• • Tender lymph nodes may be felt behind or below the ear.
  • No mastoid tenderness — this helps differentiate otitis externa from a middle ear infection with mastoiditis.

Further Tests (for atypical or refractory cases)

• Culture of ear discharge: to identify resistant or unusual organisms.

• Glucose testing: to rule out undiagnosed diabetes.

• Imaging (CT/MRI): if malignant otitis externa or abscess is suspected.

• Audiogram: to document hearing if hearing loss is persistent or unexplained.

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Treatment

1. Canal Cleaning

• Crucial for success: removes debris and allows drops to penetrate. 

• Done by a clinician under direct view with a microscope (do NOT attempt at home) using suction or gentle dry mopping under magnification.

• Avoid aggressive irrigation if eardrum integrity is uncertain.

2. Topical Therapy (Drops)

• First-line treatment for most cases.

• Combination drops: fluoroquinolone antibiotics (ciprofloxacin or ofloxacin) +/- steroids (dexamethasone or hydrocortisone). Steroids are not always prescribed.
  
  
  • *** These are the ONLY safe drops to use if a perforated eardrum is suspected. Other drops may be toxic to the ear.

• Dosage: usually 4 drops, twice daily for 7–10 days.

• Sometimes, instead of using antibiotic drops, one can use acidifying solutions (2% acetic acid) to help restore normal pH. While not usually the first choice for treating otitis externa, they’re often recommended as "routine care" for people who get frequent ear. For example, regular swimmers can use an acidifying solution after each swim to help prevent infections.

• For fungal otitis externa: clotrimazole, nystatin, or fluconazole drops.

  • These drops are toxic, must avoid if a perforated eardrum is suspected (or if you are not sure about the status of the eardrum)

3. Pain Management

• NSAIDs (ibuprofen) or acetaminophen for discomfort.

• Warm compresses can soothe pain.

4. Ear Wick Placement

• In severe swelling, a small sponge (called "wick") may be inserted to deliver drops deeper into the canal.

• The wick gently expands as it absorbs the ear drops, helping the medication reach deeper and stay in place. As it expands, it also relieves pressure by pushing back the swelling. The wick is typically removed after 7 days, but it often slips out on its own as the swelling goes down.
  

   

5. Systemic Antibiotics

• These are oral (by mouth) or intravenous antibiotics. 

• Rarely needed unless infection spreads beyond the ear canal or patient is immunocompromised.

• Oral ciprofloxacin is commonly used if systemic therapy is indicated.

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Treatment of Refractory or Chronic Cases

When symptoms persist despite 7 days of appropriate therapy:

1. Re-evaluate for incomplete cleaning or persistent moisture.

2. Obtain a bacterial/fungal culture to rule out resistant organisms.

3. Consider fungus or allergic contact dermatitis (form of skin irritation).

4. Long-term drops that contain steroids or that can acidify the ear (vinegar mix for example) for chronic inflammation.

5. Surgical widening (canalplasty) in cases of recurrent obstruction or stenosis.

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Complications

Although most cases of otitis externa resolve with topical treatment, in some situations the infection spreads beyond the ear canal. It can involve the surrounding skin, the ear cartilage, or even the temporal bone. Recognizing the differences between these complications is crucial, as their management differs significantly.

Early (Acute) Complications

1. Cellulitis:
This is an infection of the skin around the ear (the outer pinna and nearby face). It causes redness, swelling, warmth, and tenderness. It is treated with oral or intravenous antibiotics that cover skin bacteria such as Staphylococcus aureus and Streptococcus species.

2. Perichondritis and Chondritis:
When the infection extends into the cartilage of the outer ear, the ear becomes red, painful, and swollen, often sparing the earlobe (which has no cartilage). This requires stronger antibiotics—sometimes intravenous—and close monitoring, as untreated cases can lead to ear deformity.

3. Osteomyelitis (Malignant Otitis Externa):
This is a rare but severe complication where the infection spreads to the skull base (the bone around the ear canal). It occurs mainly in people with diabetes or weakened immune systems. Symptoms include persistent deep ear pain (usually for 4 weeks or more), persistent foul discharge, and sometimes facial weakness. Management requires hospitalization, prolonged intravenous antibiotics (often targeting Pseudomonas aeruginosa), and imaging studies to assess bone involvement.

Long-Term Complications

• Chronic otitis externa with thickened, scaly canal skin. Overtime (long period), chronic otitis external will lead to medial canal fibrosis, where the eardrum and skin are so thickened that they completely close off the ear canal. The eardrum no longer becomes visible! This leads to hearing loss.

• Stenosis (narrowing) of the ear canal leading to recurrent blockage.

• Eardrum perforation if infection extends inward.

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Prevention and Good Ear Hygiene

For advice on the best ear hygiene, you can read this article.   

1. Keep the ears dry:

   • Use earplugs or swim caps while swimming.

   • After swimming, tilt the head and gently pull the ear to help water drain.

   • Dry the outer ear with a towel—never insert anything inside.

   • You can even use the hair dryer on the cold setting to evaporate the water in the ear after a swim or shower.  
     
     

2. Avoid cotton swabs or sharp objects:

   • These remove protective wax and can scratch the skin.

3. After water exposure:

   • If prone to infections, use preventive drops (equal parts white vinegar and water, or equal parts white vinegar and rubbing alcohol) to acidify and dry the canal.

   • Do not use if there’s a perforated eardrum or tubes.

4. Manage underlying skin disorders:

   • Treat eczema or dermatitis promptly with prescribed topical creams.

5. Limit earbud or hearing aid use during infection or if moisture accumulates.

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Conclusion

Otitis externa is a common, painful, but highly treatable ear canal infection. Recognizing early symptoms—itching, pain with touch, and discharge—allows for quick management and prevents complications.

For most people, simple measures such as keeping the ears dry, avoiding trauma, and using topical drops correctly ensure complete recovery. In diabetics or those with persistent pain, prompt medical evaluation is critical to rule out malignant otitis externa.

Healthy ear habits go a long way toward ensuring your ears stay comfortable, infection-free, and ready to hear the world around you.