Swimmer's ear: what helps, and why ear drops beat antibiotic pills

Swimmer's ear — the doctor's name for it is acute otitis externa, inflammation of the ear canal — can usually be cleared with a course of ear drops [s1]. The evidence points firmly away from antibiotic tablets for a straightforward case: the main guideline tells clinicians not to start with oral antibiotics for uncomplicated disease [s2], and it treats pain relief as being as important as any antimicrobial [s2]. What the drops contain matters less than most people assume.

What the trials show

A Cochrane review gathered 19 randomised controlled trials with 3,382 participants to compare treatments for acute otitis externa, though it cautioned that the overall quality of the studies was low [s1]. Topical antimicrobial drops containing a steroid were clearly better than placebo drops (odds ratio 11, 95% confidence interval 2.00 to 60.57; one trial) [s1]. But when the various active drops were compared head to head, the review found no clinically meaningful differences in cure rates between most of them [s1] — meaning the choice between one antibiotic drop and another matters far less than simply using an effective one and using it properly.

There was one notable exception. A high-quality trial found acetic acid (an acidifying drop that makes the canal hostile to bacteria) significantly less effective than antibiotic-plus-steroid drops, both at two weeks (OR 0.29, 95% CI 0.13 to 0.62) and at three weeks (OR 0.25, 95% CI 0.11 to 0.58) [s1]. And adding an oral antihistamine on top of a topical steroid did not help: cure rates were 100% (15 of 15) with the antihistamine and 94% (14 of 15) without it at three weeks [s1]. A separate low-quality trial comparing quinolone antibiotics with non-quinolone antibiotics found no difference in cure rate either [s1]. Notably, no trial in the review actually tested the effect of ear cleaning, a routine part of care [s1] — a reminder of how much everyday practice rests on custom rather than trial evidence.

Drops, not pills

The American Academy of Otolaryngology's 2014 guideline on acute otitis externa makes two strong recommendations that shape sensible treatment [s2]. The first is to assess how much pain the person is in and to recommend pain relief matched to its severity — otitis externa can hurt considerably, and under-treating that is a common failing [s2]. The second is not to prescribe systemic antibiotics as the initial treatment for diffuse, uncomplicated swimmer's ear, unless the infection has spread beyond the ear canal or the person has specific risk factors — such as diabetes or a weakened immune system — that call for it [s2]. Delivering the drug straight to the canal as drops reaches a far higher concentration where it is needed while sparing the rest of the body, which is why the antibiotic tablet many people expect is usually the wrong tool. The guideline also asks clinicians to tell swimmer's ear apart from other causes of a painful, discharging ear before treating [s2].

Why the eardrum matters

One reason a clinician examines the ear before handing over drops is the eardrum. If it is perforated, some drops can reach the middle ear, so the choice of preparation changes — which is part of why self-selecting an old bottle of drops from the cupboard is not a good idea. It is also why the sensible prevention advice for swimmer's ear centres on keeping the canal dry and intact: drying the ears after swimming, and not poking at wax or the canal wall with cotton buds, a point that overlaps with coverage of safe earwax removal.

When to see a doctor

The evidence here concerns ordinary, uncomplicated swimmer's ear [s2]. Seek prompt care if the pain is severe, if redness or swelling spreads onto the outer ear or the face, if there is fever, if hearing drops markedly, or if symptoms do not begin to settle on treatment. People with diabetes or a weakened immune system need lower thresholds still, because in them a canal infection can rarely progress to a dangerous deep-tissue infection. Whether a particular ear needs cleaning, which drop is safe given the state of the eardrum, and whether tablets are warranted are clinical judgements this article does not make — but for most people, most of the time, swimmer's ear is a drops-and-pain-relief problem, not a tablets problem.