What is the treatment for otitis externa?

Treatment of Otitis Externa

The first-line treatment for otitis externa is topical antimicrobial therapy with aural toilet to ensure medication delivery to the infected ear canal. 1

Diagnosis and Assessment

Otitis externa (OE) is a cellulitis of the ear canal skin and subdermis characterized by:

• Tenderness of the tragus, pinna, or both (often intense)
• Erythema and swelling of the canal
• Variable discharge
• Pain that is limited to the external auditory canal

Microbiology

• Nearly 98% of acute otitis externa (AOE) in North America is bacterial
• Most common pathogens:
  • Pseudomonas aeruginosa (20-60%)
  • Staphylococcus aureus (10-70%)
  • Often polymicrobial 1, 2

Modifying Factors to Assess

Before initiating treatment, identify factors that may modify management:

• Nonintact tympanic membrane or tympanostomy tubes
• Diabetes
• Immunocompromised state
• Prior radiotherapy 1

Treatment Algorithm

1. Aural Toilet

• Essential first step to ensure drug delivery
• Remove debris, obstructing cerumen, or foreign objects
• Methods:
  • Gentle lavage with body-temperature water/saline (contraindicated in diabetic or immunocompromised patients)
  • Suction or dry mopping with cotton-tipped applicator
  • May require placement of a wick if canal is severely edematous 1

2. Topical Antimicrobial Therapy

• First-line treatment: Topical antibiotic drops

  • Fluoroquinolones (e.g., ciprofloxacin 0.2% or ofloxacin 0.3%)
    • Dosing: Twice daily for 7 days 3, 4
    • Safe for use with non-intact tympanic membranes 5
  • Alternative: Acidifying solutions with hydrocortisone (2% acetic acid with hydrocortisone) 1, 6

• Administration technique:

  • Lie down 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 to help penetration 1

3. Pain Management

• Assess pain severity and treat accordingly
• Options:
  • Mild to moderate pain: Acetaminophen or NSAIDs
  • Moderate to severe pain: NSAIDs plus opioid (e.g., oxycodone, hydrocodone)
  • Fixed interval dosing may be more effective than as-needed 1

4. Special Situations

Non-intact Tympanic Membrane

• Use non-ototoxic preparations (fluoroquinolones preferred)
• Avoid aminoglycoside-containing drops 1, 5

Diabetic or Immunocompromised Patients

• Monitor closely for necrotizing otitis externa
• Avoid ear canal irrigation
• Consider systemic antibiotics in addition to topical therapy
• Watch for fungal superinfection (otomycosis) 1

Fungal Infection (Otomycosis)

• Suspect if patient fails to respond to initial topical antibiotic therapy
• Appears as white debris (Candida) or black-dotted white plug (Aspergillus)
• Treatment: Debridement plus topical antifungal therapy 1, 2

Prevention

Preventive measures include:

• Keeping ears dry
• Using acidifying drops before/after swimming
• Drying ear canal with hair dryer
• Avoiding manipulation of the ear canal
• Using ear plugs while swimming 1, 6

Common Pitfalls and Caveats

1. Inadequate cleaning: Failure to remove debris can prevent medication from reaching infected areas
2. Improper drop administration: Poor technique reduces effectiveness
3. Overuse of cotton swabs: Can traumatize canal and worsen infection
4. Missing necrotizing otitis externa: Watch for granulation tissue, persistent pain, or cranial nerve involvement in high-risk patients
5. Undertreating pain: OE pain can be severe and requires adequate analgesia
6. Using ototoxic drops with perforated tympanic membrane: Can cause sensorineural hearing loss 1

Treatment Response

Most patients with uncomplicated AOE should show improvement within 48-72 hours of initiating appropriate topical therapy. If no improvement occurs after one week, cultures may help guide further treatment 3, 4.