What is the treatment regimen for otitis externa using acetic acid ear drops?

Treatment Regimen for Acetic Acid Ear Drops in Acute Otitis Externa

Acetic acid ear drops should be instilled 3-5 drops into the affected ear canal 3-4 times daily for at least 7 days, with initial placement of a cotton wick saturated with the solution kept moist every 4-6 hours for the first 24 hours. 1

Initial Treatment Setup

For optimal effectiveness, the ear canal must be thoroughly cleaned of all cerumen and debris before starting treatment to allow direct contact with infected surfaces. 1 This aural toilet is essential even though it lacks randomized controlled trial evidence, as it improves medication penetration. 2

Wick Placement Protocol

• Insert a cotton wick saturated with acetic acid solution into the ear canal at the initial visit. 1
• Instruct the patient to keep the wick moist by adding 3-5 drops every 4-6 hours for the first 24 hours. 1
• The wick may be removed after 24 hours, but if it falls out on its own, this indicates improving inflammation and is a positive sign. 2, 3
• Do not allow patients to remove the wick themselves unless specifically instructed. 3

Ongoing Treatment After Wick Removal

After the initial 24-hour wick period, patients should continue instilling 5 drops of acetic acid solution 3-4 times daily. 1 In pediatric patients, 3-4 drops may be sufficient due to smaller ear canal capacity. 1

Proper Administration Technique

• Have someone else administer the drops if possible, as only 40% of patients self-administer correctly during the first 3 days. 3
• Lie down with the affected ear facing upward and fill the ear canal completely with drops. 2, 3
• Remain in this position for 3-5 minutes using a timer to ensure adequate penetration. 2
• Gently move the ear to-and-fro or press the tragus with an in/out movement to help distribute medication. 2
• After 3-5 minutes, sit up and wipe off excess drops. 3

Treatment Duration

Continue acetic acid drops for at least 7 days, even if symptoms improve sooner, to prevent relapse. 2 If symptoms persist beyond 7 days, notify the physician and continue drops until symptoms resolve for a maximum of 7 additional days. 2

Most patients experience improvement within 48-72 hours of starting appropriate therapy. 3, 4

Critical Precautions During Treatment

• Keep the ear dry throughout treatment by covering the ear canal opening with an earplug or cotton with petroleum jelly before showering or hair washing. 2, 3
• Avoid scratching, touching, or inserting anything into the ear canal, including cotton-tipped swabs. 2, 3
• Do not attempt to clean the ear yourself as the canal is tender and easily damaged. 2, 3
• Check with your physician regarding swimming or water activities during and after infection. 2

Pain Management

Use oral pain medication for relief during the first few days until the ear drops begin working, as it typically takes at least 48 hours to feel better from topical therapy. 2, 4 Pain-relieving anesthetic ear drops are not recommended as they can mask symptoms of delayed treatment response. 2, 4

Important Efficacy Caveat

While acetic acid is effective and comparable to antibiotic/steroid drops at week 1, it becomes significantly less effective when treatment extends beyond this point. 5 One high-quality trial showed acetic acid had significantly lower cure rates at 2 and 3 weeks compared to antibiotic/steroid drops (OR 0.29 and OR 0.25 respectively). 5 Additionally, patient symptoms lasted approximately 2 days longer with acetic acid compared to antibiotic/steroid treatment. 5

For prophylaxis after moisture exposure, 2% acetic acid combined with hydrocortisone is effective, though formal clinical trial data are lacking. 6

Side Effects and Warning Signs

Acetic acid ear drops are generally safe and well tolerated. 2 However:

• Some patients may experience local rash, itching, irritation, or discomfort, though rarely severe enough to discontinue treatment. 2
• If you taste the ear drops, this indicates a possible tympanic membrane perforation—inform your physician immediately. 2, 3
• Contact your physician if drops become painful or unexpected symptoms develop. 2