PEARLS No. 240, March 2010, written by Brian R McAvoy

Clinical question
How effective are interventions for acute otitis externa?  

Bottom line
Topical treatments alone were effective in treating acute otitis externa. Topical treatments in the review included antiseptic, antibiotic, steroid, antibiotic/steroid, antiseptic/steroid, antiseptic/antibiotic/steroid, antibiotic/steroid/antifungal and antiseptic/astringent treatments. There was little to choose between these treatments in terms of effectiveness. Additional oral antibiotics were not required. However, when treatment needed to be extended beyond 1 week, acetic acid drops appeared to be less effective than antibiotic/steroid drops. In addition, symptoms persisted for 2 days longer in those treated with acetic acid. More research is needed to determine the effectiveness of steroid-only drops. Patients treated with antibiotic/steroid drops can expect their symptoms to last for approximately 6 days after treatment has begun.  


Caveat
The findings of the review may not be wholly relevant to primary care as most of the trials were conducted in a hospital setting and over half involved ear cleaning (generally not available in primary care) as part of the treatment. No trials evaluated the effectiveness of ear cleaning. Given that most topical treatments are equally effective, it would appear that in most cases the preferred choice of topical treatment may be determined by other factors, such as risk of ototoxicity, risk of contact sensitivity, risk of developing resistance, availability, cost and dosing schedule. Factors such as speed of healing and pain relief are yet to be determined for many topical treatments and may also influence this decision.  

Context
Acute otitis externa is an inflammatory condition of the ear canal, with or without infection. Symptoms include ear discomfort, itchiness, discharge and impaired hearing. The condition is also known as "swimmer's ear" and can usually be treated successfully with a course of ear drops.  

Cochrane Systematic Review
Kaushik V et al. Interventions for acute otitis externa. Cochrane Reviews 2010, Issue 1. Article No. CD004740. DOI: 10.1002/14651858.CD004740.pub2. This review contains 19 trials involving 3382 participants.