What is the treatment for otitis externa?

Treatment of Otitis Externa

Topical antimicrobial therapy is the first-line treatment for uncomplicated acute otitis externa (AOE), while systemic antibiotics should not be prescribed as initial therapy unless there is extension beyond the ear canal or specific host factors requiring systemic treatment. 1, 2

Diagnosis and Assessment

• AOE is a cellulitis of the ear canal skin and subdermis with acute inflammation and variable edema, presenting with symptoms such as ear pain, itching, or fullness, with or without hearing loss 1, 2
• Nearly 98% of AOE cases in North America are bacterial, with Pseudomonas aeruginosa (20-60%) and Staphylococcus aureus (10-70%) being the most common pathogens, often as polymicrobial infections 1, 2
• Clinicians should assess for modifying factors that may alter management, including non-intact tympanic membrane, tympanostomy tubes, diabetes, immunocompromised state, and prior radiotherapy 1, 3

First-Line Treatment

• Topical antimicrobial therapy delivers concentrations 100-1000 times higher than systemic therapy, making it more effective against potential pathogens 1, 2
• Aural toilet (gentle suction, dry mopping, irrigation, or removal of obstructing debris) should be performed before administering drops to ensure medication reaches infected tissues 3
• Various topical preparations are approved by the FDA for treating AOE, including those containing antibiotics (aminoglycosides, polymyxin B, quinolones), steroids, or low-pH antiseptics 1
• Meta-analyses have shown no significant differences in clinical outcomes based on class of drug (antibiotic vs antiseptic), quinolone versus non-quinolone preparations, or monotherapy versus combination drugs with or without steroids 1

Pain Management

• Clinicians should assess patients with AOE for pain and recommend analgesic treatment based on pain severity 1, 3
• Pain typically improves within 48-72 hours of starting appropriate treatment 2, 3

Special Considerations

• For patients with non-intact tympanic membranes (perforation or tympanostomy tubes), non-ototoxic preparations such as quinolones should be used 1, 3
• Declining susceptibility to neomycin and polymyxin B has been observed in pathogens causing otitis externa, while susceptibility to quinolones like ofloxacin has remained stable 4
• Patients with diabetes or immunocompromised states require special consideration as they are susceptible to otomycosis and necrotizing otitis externa 2, 3
• If fungal infection is suspected, topical antifungal therapy and debridement are recommended, avoiding antibacterial drops that may promote fungal overgrowth 3

When to Use Systemic Antibiotics

• Systemic antibiotics should not be prescribed as initial therapy for uncomplicated AOE 1, 3
• Oral antibiotics should be reserved for specific circumstances:
  • Extension of infection beyond the ear canal
  • Patients with diabetes or immunocompromised status
  • When topical therapy cannot reach the infected area or has failed 3

Treatment Expectations and Follow-up

• Patients should expect improvement within 48-72 hours of initiating appropriate topical therapy 2, 3
• If no improvement occurs within this timeframe, consider treatment failure, allergic contact dermatitis, or misdiagnosis 2
• Complete the full course of therapy even if symptoms resolve early 3

Prevention Strategies

• Strategies to reduce recurrence include removing obstructing cerumen, using acidifying ear drops before/after swimming, drying the ear canal with a hair dryer, and using ear plugs while swimming 2

Common Pitfalls to Avoid

• Overuse of oral antibiotics for uncomplicated cases 3, 5
• Using ototoxic preparations when tympanic membrane integrity is compromised 3
• Inadequate pain management 3
• Failure to remove debris before administering drops 3
• Missing fungal infections, especially in patients with diabetes or those who fail to respond to antibacterial therapy 3