Topical antiseptics for chronic suppurative otitis media.

BACKGROUND

Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and often polymicrobial 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. Topical antiseptics, a possible treatment for CSOM, inhibit the micro-organisms that may be responsible for the infection. Antiseptics can be used alone or in addition to other treatments for CSOM, such as antibiotics or ear cleaning (aural toileting). However, the effects of topical antiseptics for CSOM remain unclear. This is an update of a review last published in 2020, with one new study added. It is one of a suite of seven Cochrane reviews evaluating the effects of non-surgical interventions for CSOM.

OBJECTIVES

To assess the effects of topical antiseptics for people with CSOM.

SEARCH METHODS

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. The date of the latest search was 15 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with at least a one-week follow-up involving participants (adults and children) who had chronic ear discharge of unknown cause or CSOM, where the ear discharge had continued for more than two weeks. The interventions were any single, or combination of, topical antiseptic agent of any class, applied directly into the ear canal as ear drops, powders, or irrigations, or as part of an aural toileting procedure. The two main comparisons were topical antiseptics (a) compared to placebo or no intervention, and (b) compared to another topical antiseptic (e.g. topical antiseptic A versus topical antiseptic B). Within each comparison, we separated studies into (a) those in which both groups of participants had received aural toileting in addition to the topical antiseptics, and those where neither group had received aural toileting, and (b) those in which both groups had received some other concomitant treatment (such as antibiotics) and those with no such concomitant treatment.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. 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; 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.

MAIN RESULTS

We found one new study (32 participants) in this update, for a total of six included studies with 435 participants (over four studies), plus 222 ears that could not be accounted for in participant numbers (in two studies). Four studies compared topical antiseptics with no treatment or placebo, and two studies compared two different topical antiseptics (boric acid versus acetic acid, and boric acid versus hydrogen peroxide). The two core comparisons of interest are reported below; other comparisons are described in the Results section of the review. No study measured health-related quality of life or ear pain. 1. Topical antiseptic versus placebo or no treatment Three studies (297 participants plus 174 ears) compared topical antiseptics with no treatment. Evidence from one study (unclear number of participants, 174 ears) is very uncertain about the effect of a single application of povidone iodine in hydroxypropyl methyl-cellulose (HPMC) on resolution of ear discharge at one week compared to HPMC alone; however, these results were only provided by ear (rather than by participant) and therefore could not be used quantitatively (very low-certainty evidence). One study (254 children; cluster-RCT) found that boric acid in alcohol ear drops with dry mopping may help resolution of ear discharge after four weeks compared with dry mopping alone, but the evidence is very uncertain (risk ratio (RR) 1.73, 95% confidence interval (CI) 1.21 to 2.47; 180 participants; very low-certainty evidence). We made adjustments to the data to account for the intracluster correlation. This study narratively described no clear differences in suspected ototoxicity or hearing outcomes between study arms, but the evidence is very uncertain (very low-certainty evidence). Evidence from one study (43 children; 58 ears) is very uncertain about the effect of antiseptics on serious complications. The study reported one case of mastoiditis and one of meningitis with focal encephalitis; however, it was unclear whether these were detected pre-randomisation or during/after treatment. 2. Topical antiseptics versus no treatment/placebo, where both study arms received systemic antibiotics One study (32 participants) compared topical povidone iodine with placebo (saline) in conjunction with oral amoxicillin and dry mopping. Topical povidone iodine with oral amoxicillin and dry mopping may increase resolution of ear discharge at one to two weeks (RR 3.25, 95% CI 1.35 to 7.84; 32 participants; low-certainty evidence). The study narratively reported no ototoxicity in the topical antiseptic arm; however, this was unclear for the placebo group, so we do not know if povidone iodine increases suspected ototoxicity (low-certainty evidence). The study did not assess resolution of ear discharge after four weeks, hearing, or serious complications.

AUTHORS' CONCLUSIONS: We are very uncertain about the effect of topical antiseptics on improving resolution of ear discharge in people with CSOM given the low and very low certainty of the evidence, which was mostly due to risk of bias and imprecision. However, there is some evidence suggesting that boric acid in alcohol ear drops with dry mopping may help resolution of ear discharge compared with dry mopping alone, and that topical povidone iodine may be more effective than placebo (where both arms used systemic beta-lactam antibiotics and dry mopping). There is insufficient evidence to draw any conclusions about harmful effects. Limitations of the review include lack of recency in data, and limited information on certain population groups or interventions.