Background: Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and infection of the middle ear and mastoid cavity, 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).
Objectives: To assess the effectiveness of antibiotics versus antiseptics for people with chronic suppurative otitis media (CSOM).
Search methods: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL; 2019, Issue 4, via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 1 April 2019. Selection criteria: We included randomised controlled trials (RCTs) with at least a one-week follow-up involving patients (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. Two comparisons were topical antiseptics compared to: a) topical antibiotics or b) systemic antibiotics. Within each comparison we separated where both groups of patients had received topical antibiotic a) alone or with aural toilet and b) on top of background treatment (such as systemic antibiotics).
Data collection and analysis: We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. 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 included hearing, serious complications and ototoxicity measured in several ways.
Main results: We identified seven studies (935 participants) across four comparisons with antibiotics compared against acetic acid, aluminium acetate, boric acid and povidone-iodine. None of the included studies reported the outcomes of quality of life or serious complications.
A. Topical antiseptic (acetic acid) versus topical antibiotics (quinolones or aminoglycosides). It is very uncertain if there is a difference in resolution of ear discharge with acetic acid compared with aminoglycosides at one to two weeks (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.72 to 1.08; 1 study; 100 participants; very low-certainty evidence). No study reported results for ear discharge after four weeks. It was very uncertain if there was more ear pain, discomfort or local irritation with acetic acid or topical antibiotics due to the low numbers of participants reporting events (RR 0.16, 95% CI 0.02 to 1.34; 2 RCTs; 189 participants; very low-certainty evidence). No differences between groups were reported narratively for hearing (quinolones) or suspected ototoxicity (aminoglycosides) (very low-certainty evidence).
B. Topical antiseptic (aluminium acetate) versus topical antibiotics. No results for the one study comparing topical antibiotics with aluminium acetate could be used in the review.
C. Topical antiseptic (boric acid) versus topical antibiotics (quinolones). One study reported more participants with resolution of ear discharge when using topical antibiotics (quinolones) compared with boric acid ear drops at between one to two weeks (risk ratio (RR) 1.56, 95% confidence interval (CI) 1.27 to 1.92; 1 study; 409 participants; moderate-certainty evidence). This means that one additional person will have resolution of ear discharge for every five people receiving topical antibiotics (compared with boric acid) at two weeks. No study reported results for ear discharge after four weeks. There was a bigger improvement in hearing in the topical antibiotic group compared to the topical antiseptic group (mean difference (MD) 2.79 decibels (dB), 95% CI 0.48 to 5.10; 1 study; 390 participants; low-certainty evidence) but this difference may not be clinically significant. There may be more ear pain, discomfort or irritation with boric acid compared with quinolones (RR 0.56, 95% CI 0.32 to 0.98; 2 studies; 510 participants; low-certainty evidence). Suspected ototoxicity was not reported.
D. Topical antiseptic (povidone-iodine) versus topical antibiotics (quinolones). It is 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 patients developed ototoxic effects (very low-certainty evidence). No results for resolution of ear discharge beyond four weeks, or ear pain, discomfort or irritation, were reported.
E. Topical antiseptic (acetic acid) + aural toileting versus topical + systemic antibiotics (quinolones). One study reported that participants receiving topical and oral antibiotics had less resolution of ear discharge compared with acetic acid ear drops and aural toileting (suction clearance every two days) at one month (RR 0.69, 95% CI 0.53 to 0.90; 100 participants). The study did not report results for resolution of ear discharge at between one to two weeks, ear pain, discomfort or irritation, hearing or suspected ototoxicity.
Authors' conclusions: Treatment of CSOM with topical antibiotics (quinolones) probably 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. Adverse events were not well reported.