Antibiotics versus topical antiseptics for chronic suppurative otitis media

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media, is a chronic inflammation and often polymicrobial infection of the middle ear and mastoid cavity. It is characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Antibiotics and antiseptics kill or inhibit the micro-organisms that may be responsible for the infection. Antibiotics can be applied topically or administered systemically via the oral or injection route. Antiseptics are always directly applied to the ear (topically).

To assess the benefits and harms of antibiotics versus antiseptics for people with chronic suppurative otitis media (CSOM).

We searched the Cochrane ENT Register, CENTRAL, Ovid MEDLINE, Ovid Embase, and five other databases. We also searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP). The latest search date was 15 June 2022.

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving adults and children who had chronic ear discharge of unknown cause or CSOM, where ear discharge had continued for more than two weeks. The intervention was any single, or combination of, antibiotic agent, whether applied topically (without steroids) or systemically. The comparison was any single, or combination of, topical antiseptic agent, applied as ear drops, powders, or irrigations, or as part of an aural toileting procedure. The comparisons were 1. topical antiseptics compared to topical antibiotics, and 2. topical antiseptics compared to systemic antibiotics. We further separated these comparisons into those in which a. both groups of participants received aural toileting in addition to the intervention, or b. both groups received some other add-on therapy treatment (such as systemic antibiotics) to both arms.

We used standard Cochrane methodology. Our primary outcomes were resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not), measured at between one week and up to two weeks, two weeks to up to four weeks, and after four weeks; health-related quality of life using a validated instrument; and ear pain (otalgia) or discomfort or local irritation. Secondary outcomes were hearing, serious complications, and ototoxicity. We used GRADE to assess the certainty of the evidence for each outcome.

This updated review included eight new studies. Overall, we identified 15 studies (2371 participants) across seven comparisons with antibiotics compared to acetic acid, aluminium acetate, boric acid, and povidone-iodine. None of the included studies reported health-related quality of life or serious complications. 1. Topical antibiotics (quinolones or aminoglycosides) versus topical antiseptic (acetic acid) We included seven studies (835 participants). Acetic acid may increase resolution of ear discharge when compared to aminoglycoside at one to two weeks (low-certainty evidence). It is very uncertain whether acetic acid may increase resolution of ear discharge at one to two weeks when compared to topical quinolone. Results after four weeks were only presented narratively. It is very uncertain whether acetic acid may cause more ear pain, discomfort, local irritation, or combinations of these compared to topical antibiotics (aminoglycosides and quinolones) (risk ratio (RR) 0.20, 95% confidence interval (CI) 0.03 to 1.12; I² = 0%; 3 studies, 277 participants; very low-certainty evidence). An additional two studies (350 participants) provided narrative results. There may be little to no difference in hearing between groups reported narratively (quinolones; low-certainty evidence). The evidence is very uncertain for serious complications (aminoglycosides) or suspected ototoxicity (aminoglycosides) (very low-certainty evidence). 2. Topical antibiotics (quinolones) versus topical antiseptic (boric acid) We included two studies (532 participants). Topical quinolones are likely to increase resolution of ear discharge at one to two weeks compared with boric acid ear drops (RR 1.86, 95% CI 1.48 to 2.35; 1 study, 411 participants; moderate-certainty evidence). This means that one additional person will have resolution of ear discharge for every four people receiving topical antibiotics (compared with boric acid) at two weeks. No study reported results for ear discharge after four weeks. There may be less ear pain, discomfort, or irritation with quinolones compared with boric acid (RR 0.56, 95% CI 0.32 to 0.98; 2 studies, 510 participants; low-certainty evidence). Suspected ototoxicity and serious complications were not reported. Topical quinolones may result in a greater improvement in mean hearing from baseline compared to topical boric acid (mean difference (MD) 2.79 decibels, 95% CI 0.48 to 5.10; 1 study, 390 participants; low-certainty evidence), but this difference may not be clinically significant. 3. Topical antibiotics (quinolones) versus topical antiseptic (povidone-iodine) We included one study (40 participants). It is very uncertain if there is a difference between quinolones and povidone-iodine with respect to resolution of ear discharge at one to two weeks (RR 1.02, 95% CI 0.82 to 1.26; 1 RCT, 39 participants; very low-certainty evidence). The study reported qualitatively that there were no differences between the groups for hearing and no participants developed ototoxic effects (very low-certainty evidence). There were no results reported for resolution of ear discharge beyond four weeks; ear pain, discomfort, or irritation; or serious complications. 4. Topical antibiotics versus topical antiseptic (aluminium acetate) We included one study (51 participants; 60 ears) that presented results for resolution of ear discharge at two to four weeks results narratively. No other results were reported. 5. Other comparisons Five studies (966 participants) were assessed over an additional three comparisons; however, these results have not been included in the abstract.

Treatment of CSOM with topical antibiotics (quinolones) likely results in an increase in resolution of ear discharge compared with boric acid at up to two weeks. There was limited evidence for the efficacy of other topical antibiotics or topical antiseptics and so we are unable to draw conclusions. Harmful effects were not well reported. Limitations of the review include lack of recent data, limitations in the quality of included studies, and limited information on certain population groups or interventions.