What is the recommended treatment for acute otitis externa?

Treatment of Acute Otitis Externa

Topical antimicrobial ear drops are the definitive first-line treatment for uncomplicated acute otitis externa—oral antibiotics should not be prescribed initially. 1, 2

Essential Pre-Treatment Step: Aural Toilet

Before administering any medication, the ear canal must be cleared of debris, cerumen, and inflammatory material to ensure drops reach infected tissue. 1, 2

• Use gentle suction, dry mopping, or irrigation with body-temperature water, saline, or hydrogen peroxide in most patients 1, 2
• In diabetic or immunocompromised patients, use only atraumatic suction under microscopic guidance—avoid irrigation as it can trigger necrotizing otitis externa 1, 2
• Place a compressed cellulose wick if severe canal edema prevents drop entry or if the tympanic membrane cannot be visualized 1, 2

Topical Antimicrobial Selection

When Tympanic Membrane Integrity Is Uncertain or Compromised

Use only non-ototoxic fluoroquinolone preparations (ofloxacin 0.3% or ciprofloxacin 0.2%) to avoid inner-ear toxicity. 1, 2, 3

• This applies to patients with known or suspected tympanic membrane perforation or tympanostomy tubes 1, 2
• Avoid aminoglycoside-containing drops (e.g., neomycin/polymyxin B) in these situations due to documented ototoxicity risk 1, 2

When Tympanic Membrane Is Intact

Any FDA-approved topical preparation is acceptable—clinical cure rates of 65-90% are achieved within 7-10 days regardless of specific agent. 1, 2, 4

• Avoid neomycin-containing preparations in patients with history of contact dermatitis, eczema, or chronic/recurrent otitis externa, as neomycin causes contact sensitivity in 13-30% of patients with chronic otitis externa 2, 5, 6
• Topical antimicrobials containing steroids are significantly more effective than placebo (OR 11; 95% CI 2.00-60.57) and accelerate pain relief 2, 4

Proper Drop Administration Technique

Only 40% of patients self-administer drops correctly during the first three days—having another person apply drops markedly improves adherence. 2

• Warm the bottle in hands for 1-2 minutes to prevent dizziness 2
• Lie with affected ear upward and instill enough drops to fill the canal completely 1, 2
• Remain in position for 3-5 minutes (use a timer) 1, 2
• Apply gentle to-and-fro movement of pinna or press tragus in/out to eliminate trapped air 1, 2
• Leave canal open to dry after administration—do not trap moisture 2

Treatment Duration

• Prescribe drops for minimum 7 days even if symptoms resolve earlier, to prevent relapse 1, 2
• If symptoms persist beyond 7 days, continue drops until resolution for maximum of 14 days total 2

Pain Management

Pain assessment and appropriate analgesia are essential—otitis externa pain can be severe and disproportionate to visual findings. 1, 6

• Mild-to-moderate pain: acetaminophen 650-1000 mg every 6 hours or ibuprofen 400-600 mg every 6 hours 2, 6
• Severe pain: short-term opioid-containing analgesics for initial 48-72 hours 1, 2, 6
• Pain typically improves within 48-72 hours of starting topical therapy 1, 2, 6
• Do not use topical anesthetic drops (e.g., benzocaine)—they are not FDA-approved for active infection and may mask treatment failure 1, 2

When Systemic Antibiotics ARE Indicated

Reserve oral antibiotics for specific circumstances only—topical therapy achieves cure rates of 77-96% versus 30-67% for oral regimens. 1, 2

Indications for systemic therapy:

• Extension of infection beyond ear canal (periauricular cellulitis or swelling) 1, 2, 6
• Diabetes mellitus or immunocompromised state 1, 2, 6
• Severe canal edema preventing adequate topical delivery despite wick placement 2, 6
• Failure to improve after 48-72 hours of appropriate topical therapy 1, 2

When indicated, use fluoroquinolones (e.g., ciprofloxacin 500 mg twice daily) to cover Pseudomonas aeruginosa and Staphylococcus aureus, which cause ~98% of cases. 1, 2, 7

Reassessment and Treatment Failure

Reassess patients within 48-72 hours if no improvement occurs. 1, 2, 6

Common causes of treatment failure:

• Inadequate drug delivery due to canal obstruction or poor adherence 1, 2, 6
• Allergic contact dermatitis from topical agents (especially neomycin or hydrocortisone) 2, 5, 6
• Fungal co-infection (otomycosis), especially in diabetics or after prolonged antibiotic use 1, 2, 6
• Incorrect diagnosis (e.g., chronic suppurative otitis media, necrotizing otitis externa) 1, 2

Special Populations: High-Risk Patients

Diabetic or immunocompromised patients require modified management:

• Monitor carefully for necrotizing otitis externa 1, 2, 6
• Avoid ear canal irrigation—use only atraumatic suction 1, 2
• Consider systemic antibiotics even for seemingly uncomplicated cases 1, 2, 6
• Higher susceptibility to fungal infections 1, 2

Patient Education and Activity Restrictions

• Keep ear dry during treatment—cover canal with earplug or petroleum-jelly-coated cotton before showering 2
• Avoid swimming and water exposure until infection resolves 2
• Do not insert cotton swabs or any objects into ear canal 2
• If patient tastes eardrops, inform clinician immediately—this indicates tympanic membrane perforation 2
• Complete full 7-day course even if symptoms resolve early 2
• Return for reassessment if symptoms don't improve within 48-72 hours or persist beyond 2 weeks 1, 2

Critical Pitfalls to Avoid

• Prescribing oral antibiotics for uncomplicated cases (occurs inappropriately in 20-40% of patients) 1, 2, 6
• Using ototoxic preparations when tympanic membrane integrity is compromised 1, 2, 6
• Skipping aural toilet before drop administration—medication cannot penetrate debris 1, 2, 6
• Inadequate pain management 2, 6
• Irrigating ear canal in diabetic or immunocompromised patients 1, 2
• Missing fungal infections, especially in high-risk patients 2, 6
• Prescribing neomycin-containing drops to patients with eczema or contact dermatitis history 2, 5
• Using ear candles—no proven efficacy and potential for harm (hearing loss, tympanic membrane perforation) 2