What is the treatment for otitis externa?

Treatment for Otitis Externa

Topical antimicrobial therapy is the first-line and definitive treatment for uncomplicated acute otitis externa, delivering drug concentrations 100-1000 times higher than oral antibiotics and effectively targeting the causative pathogens Pseudomonas aeruginosa and Staphylococcus aureus. 1, 2, 3

Initial Management Steps

Aural Toilet (Ear Canal Cleaning)

• Remove obstructing debris, cerumen, or foreign objects before administering topical drops to ensure medication reaches infected tissues 1, 3
• Perform gentle suction, dry mopping with cotton-tipped applicator, or irrigation using body-temperature water, saline, or hydrogen peroxide 1, 3
• Caution in diabetic or immunocompromised patients: Avoid aggressive irrigation with tap water; use atraumatic suctioning under microscopic guidance instead, as irrigation has been implicated in triggering malignant (necrotizing) otitis externa 1

Wick Placement

• Place a compressed cellulose wick if the ear canal is severely edematous or if most of the tympanic membrane cannot be visualized 1, 3
• The wick expands when moistened, facilitating drug delivery through the swollen canal 1
• Moisten the wick with aqueous solution before applying viscous medications 1
• The wick typically falls out within 24 hours as edema subsides, which is a positive sign 1

Topical Antimicrobial Selection

For Intact Tympanic Membrane

• Prescribe topical preparations containing aminoglycosides, polymyxin B, fluoroquinolones, or acidifying agents 3
• Ofloxacin 0.3% otic solution once daily for 7 days achieves 91% cure rates 4
• Adding topical corticosteroids to antimicrobials reduces inflammation and hastens pain relief 3, 5

For Perforated Tympanic Membrane or Tympanostomy Tubes

• Use ONLY non-ototoxic fluoroquinolone preparations (ciprofloxacin or ofloxacin) 2, 3
• Avoid aminoglycosides (neomycin) and polymyxin B due to ototoxicity risk 3, 6

Important Note on Resistance

• Neomycin and polymyxin B resistance has increased significantly, with mean MICs rising above breakpoints, while fluoroquinolone susceptibility remains stable 7
• Acetic acid drops are less effective than antibiotic/steroid combinations when treatment extends beyond one week 8

Proper Drop Administration

Instruct patients or caregivers on the following technique (having another person administer drops significantly improves adherence): 1, 3

• Lie down with affected ear facing upward 1, 3
• Fill the ear canal completely with drops (amount varies by age: 5 drops for children <13 years, 10 drops for adolescents/adults ≥13 years) 4
• Remain in this position for 3-5 minutes (use a timer for children) 1, 3
• Apply gentle to-and-fro movement of the pinna or tragal pumping to eliminate trapped air 1, 3
• Keep ear dry during treatment 3

Pain Management

• Assess pain severity and prescribe appropriate analgesics based on intensity 2, 3
• Pain typically improves within 48-72 hours of starting treatment 2, 3
• For severe pain, consider short-term opioid-containing analgesics for the initial 48-72 hours 3

When to Use Oral Antibiotics

Oral antibiotics should NOT be used for uncomplicated otitis externa 1, 2, 3. Reserve systemic antibiotics for:

• Extension of infection beyond the ear canal (cellulitis of pinna or periauricular tissues) 2, 3
• Diabetic patients at risk for necrotizing otitis externa 2, 3, 5
• Immunocompromised patients 2, 3, 5
• When topical therapy cannot reach the infected area or has failed 2, 3

If oral antibiotics are indicated, prescribe fluoroquinolones (ciprofloxacin) for Pseudomonas and Staphylococcus coverage 2. Note that 20-40% of patients inappropriately receive oral antibiotics, and most prescribed oral agents are inactive against the causative pathogens 1, 2.

Special Considerations

Fungal Otitis Externa (Otomycosis)

• Suspect in patients who fail antibacterial therapy, especially those with diabetes 2, 3
• Treat with topical antifungals and debridement 2
• Avoid antibacterial drops that promote fungal overgrowth 2, 3

High-Risk Patients (Diabetes, Immunocompromised)

• Monitor carefully for necrotizing otitis externa, which can initially present identically to uncomplicated otitis externa 2
• Consider adding systemic antibiotics even for localized disease 2, 3
• Patients with prediabetes are also at increased risk for otomycosis and necrotizing disease 2

Expected Timeline and Follow-Up

• Symptoms should improve within 48-72 hours 2, 3
• 68% of patients are cured within 7 days 4
• Reassess patients who show no improvement at 48-72 hours 2, 3
• Complete the full 7-10 day course even if symptoms resolve early 3
• Average symptom duration with antibiotic/steroid drops is approximately 6 days 8

Common Pitfalls to Avoid

• Prescribing oral antibiotics for uncomplicated cases (occurs in 20-40% of patients inappropriately) 1, 2, 3
• Using ototoxic preparations (neomycin, polymyxin B) when tympanic membrane integrity is uncertain or compromised 2, 3
• Failing to remove debris before administering drops, resulting in inadequate drug delivery 2, 3
• Inadequate pain management 2, 3
• Missing fungal infections, particularly in diabetic patients or those failing antibacterial therapy 2, 3
• Poor adherence: Only 40% of patients self-administering drops do so correctly in the first 3 days; having another person administer drops significantly improves outcomes 1