What is the treatment for otitis externa?

Treatment for Otitis Externa

The first-line treatment for otitis externa is topical antimicrobial therapy, not oral antibiotics, as topical preparations deliver high concentrations of medication directly to the infected tissue while minimizing systemic side effects. 1

Diagnosis and Initial Assessment

Otitis externa (OE) is characterized by:

• Rapid onset (within 48 hours) of symptoms in the past 3 weeks
• Ear canal inflammation with otalgia (often severe), itching, or fullness
• Tenderness of the tragus, pinna, or both that is disproportionate to visual inspection
• Diffuse ear canal edema, erythema, or both (with or without otorrhea)

Treatment Algorithm

Step 1: Pain Management

• Assess pain severity and prescribe appropriate analgesics
• For mild pain: NSAIDs or acetaminophen
• For moderate to severe pain: Consider short-term opioid-containing analgesics (limited doses for initial 48-72 hours) 1

Step 2: Determine Need for Systemic Therapy

• Systemic antibiotics are NOT indicated for uncomplicated otitis externa 1
• Reserve systemic therapy ONLY for:
  • Extension of infection beyond the ear canal
  • Specific host factors (diabetes, immunocompromised state)

Step 3: Select Topical Therapy

• For intact tympanic membrane:

  • Antibiotic drops with or without steroid component
  • Common options include:
    • Neomycin/polymyxin B/hydrocortisone combination 2, 3
    • Fluoroquinolone preparations (e.g., ofloxacin) 4, 5

• For perforated tympanic membrane or tympanostomy tubes:

  • Non-ototoxic preparations only (avoid aminoglycosides like neomycin)
  • Fluoroquinolone preparations are preferred 1

Step 4: Ensure Proper Drug Delivery

• Clear obstructing debris through aural toilet (suction, dry mopping, irrigation)
• Place a wick if ear canal is severely swollen
• Educate patient on proper administration technique:
  • Lie with affected ear up
  • Fill ear canal with drops
  • Remain in position for 3-5 minutes
  • Use gentle to-and-fro movement of the ear or tragal pumping 1

Step 5: Follow-up and Reassessment

• Assess for clinical improvement within 48-72 hours
• If no improvement, reassess for:
  • Obstructed ear canal
  • Poor adherence to therapy
  • Misdiagnosis
  • Need for culture if resistant organisms suspected 1

Important Considerations

Microbiology

• Primary pathogens: Pseudomonas aeruginosa (20-60%) and Staphylococcus aureus (10-70%)
• Often polymicrobial infections 1

Antibiotic Selection Considerations

• Increasing resistance to neomycin and polymyxin B has been reported 6
• However, topical preparations achieve such high concentrations that this may be less clinically relevant than with systemic therapy 1, 7
• Fluoroquinolones have maintained good susceptibility patterns 6

Duration of Therapy

• Typical course is 7-10 days
• Continue treatment for at least 7 days even if symptoms improve sooner 1
• Do not continue treatment beyond 10 days without reassessment 2, 3

Common Pitfalls to Avoid

1. Using oral antibiotics as first-line therapy - Oral antibiotics have limited utility for uncomplicated OE and may select for resistant organisms 1
2. Inadequate pain management - OE can be extremely painful; ensure appropriate analgesia
3. Poor drug delivery - Failure to clear obstructing debris or properly instruct on drop administration
4. Inappropriate antibiotic selection - Using potentially ototoxic drops in patients with perforated tympanic membranes
5. Premature discontinuation - Stopping therapy too soon can lead to relapse

Prevention Strategies

• Water precautions during treatment
• For recurrent cases:
  • Acidifying drops before/after swimming
  • Drying ear canal with hair dryer
  • Using ear plugs while swimming
  • Avoiding trauma to the ear canal 1

Special Populations

• Children: Same principles apply for children ≥2 years old
• Immunocompromised/Diabetic patients: Lower threshold for systemic therapy and closer monitoring
• Hearing aid users: Temporary discontinuation of hearing aid use may be necessary during treatment