What is the treatment for otitis externa?

Treatment of Otitis Externa

Topical antimicrobial therapy is the mainstay of treatment for uncomplicated acute otitis externa, achieving clinical resolution in 65-90% of patients within 7-10 days and demonstrating superior outcomes to oral antibiotics. 1, 2

Initial Management Steps

Ear Canal Preparation

• Clear the ear canal of inflammatory debris, obstructing cerumen, or foreign objects before administering topical medication to ensure medication reaches infected tissues 1, 2
• Use gentle lavage with body-temperature water, saline, or hydrogen peroxide for cleaning 1
• In diabetic or immunocompromised patients, avoid irrigation and use only atraumatic cleaning with aural suctioning to prevent complications 1

Assessment of Modifying Factors

• Evaluate for nonintact tympanic membrane, tympanostomy tubes, diabetes, immunocompromised state, or prior radiotherapy, as these alter management 1, 3
• Assess pain severity to guide appropriate analgesic treatment 1, 2
• Check for signs of fungal infection, especially in diabetic patients or those failing antibacterial therapy 1, 2

First-Line Topical Antimicrobial Therapy

For Intact Tympanic Membrane

• Prescribe topical antimicrobial preparations effective against Pseudomonas aeruginosa (20-60% of cases) and Staphylococcus aureus (10-70% of cases) 1, 3
• Ofloxacin 0.3% otic solution is recommended as a first-line option 1
• Neomycin/polymyxin B/hydrocortisone preparations are reasonable first-line therapy when the tympanic membrane is intact 4
• Meta-analyses show no significant differences in clinical outcomes between antibiotic classes, quinolone versus non-quinolone preparations, or monotherapy versus combination drugs 3

Important caveat: Recent data shows declining susceptibility to neomycin and polymyxin B, with mean MICs increasing above breakpoints for polymyxin B, while ofloxacin susceptibility remains stable 5. This supports quinolone preparations as preferred agents despite guideline statements of equivalence.

For Perforated Tympanic Membrane or Tympanostomy Tubes

• Use only non-ototoxic preparations such as quinolone drops (e.g., ofloxacin, ciprofloxacin) to avoid ototoxicity 1, 2, 3
• Avoid aminoglycosides (neomycin) and polymyxin B in these patients 2, 3

Proper Administration Technique

• Have the patient lie with the affected ear upward and instill enough drops to fill the ear canal 1
• Maintain this position for 3-5 minutes to facilitate penetration 1
• Apply gentle to-and-fro movement of the ear or press the tragus with in/out movement to help drops penetrate 1
• Continue eardrops for at least 7 days, even if symptoms improve sooner, to prevent relapse 1

Wick Placement

• Place a wick in the ear canal if edema prevents drop entry or if most of the tympanic membrane cannot be visualized 1

Pain Management

• Prescribe analgesics based on pain severity 1, 2, 3
• Inform patients that pain typically improves within 48-72 hours of starting treatment 1, 2, 3
• Topical corticosteroid-containing preparations may help resolve symptoms more quickly by reducing swelling, erythema, and secretions 6, 4

When to Use Systemic Antibiotics

Reserve oral antibiotics for specific circumstances only—they should NOT be used as initial therapy for uncomplicated otitis externa 2, 3. Approximately 20-40% of patients inappropriately receive oral antibiotics 2.

Indications for Oral Antibiotics:

• Extension of infection beyond the ear canal 1, 2, 3
• Patients with diabetes or immunocompromised status 1, 2, 3
• When topical therapy cannot reach the infected area or has failed 1, 2, 3

Antibiotic Selection:

• Fluoroquinolones (e.g., ciprofloxacin) are first-line for oral therapy, providing coverage against Pseudomonas aeruginosa and Staphylococcus aureus 2
• Most oral antibiotics prescribed for otitis externa are inactive against P. aeruginosa 2
• Topical therapy delivers antimicrobial concentrations 100-1000 times higher than systemic therapy 2, 3

Special Populations

Diabetic and Immunocompromised Patients

• Monitor carefully for signs of necrotizing otitis externa, which can present initially with symptoms similar to uncomplicated otitis externa 2, 3
• Consider adding systemic antibiotics in these high-risk patients 1, 2
• These patients are more susceptible to otomycosis 2, 3
• Avoid ear canal irrigation—use only atraumatic cleaning 1

Fungal Otitis Externa

• Use topical antifungal therapy and debridement for suspected fungal infection 1, 2
• Avoid antibacterial drops that may promote fungal overgrowth 1, 2
• Suspect fungal infection in diabetic patients or those failing antibacterial therapy 1, 2, 3

Follow-Up and Treatment Failure

• Reassess patients within 48-72 hours if no improvement is seen 2, 3
• If symptoms persist beyond 7 days, continue drops until symptoms resolve for a maximum of 7 additional days 1

Reasons for Treatment Failure:

• Inadequate drug delivery due to canal obstruction 2
• Poor adherence to therapy (patients tend to overadminister when pain is greatest and underadminister as symptoms resolve) 2
• Incorrect diagnosis 2
• Fungal infection 2
• Contact dermatitis from topical agents 2

Activity Restrictions

• Avoid scratching or touching the ear and do not insert anything into the ear canal, including cotton-tipped swabs 1
• Cover the opening of the ear canal with an earplug or cotton with petroleum jelly prior to showering or hair washing 1
• Consult with a doctor regarding swimming or other water activities during or soon after infection 1

Common Pitfalls to Avoid

• Overuse of oral antibiotics for uncomplicated cases 1, 2, 3
• Using ototoxic preparations (aminoglycosides, polymyxin B) when tympanic membrane integrity is compromised 1, 2, 3
• Inadequate pain management 1, 2, 3
• Failure to remove debris before administering drops 1, 2, 3
• Missing fungal infections, especially in diabetic patients 1, 2, 3