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 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, one of the possible treatments 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). Antiseptics or their application can cause irritation of the skin of the outer ear, manifesting as discomfort, pain or itching. Some antiseptics (such as alcohol) may have the potential to be toxic to the inner ear (ototoxicity), with a possible increased risk of causing sensorineural hearing loss, dizziness or tinnitus.

Objectives: To assess the effects of topical antiseptics for people with chronic suppurative otitis media.

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Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials.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 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. Two main comparisons were topical antiseptics compared to: a) placebo or no intervention; and b) another topical antiseptic (e.g. topical antiseptic A versus topical antiseptic B). Within each comparison we separated studies where both groups of patients had received topical antiseptics a) alone or with aural toileting and b) on top of antibiotic treatment.

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; ear pain (otalgia) or discomfort or local irritation. Secondary outcomes included hearing, serious complications and ototoxicity measured in several ways.

Main results: Five studies were included. It was not possible to calculate the total number of participants as two studies only provided the number of ears included in the study. A. Topical antiseptic (boric acid) versus placebo or no treatment (all patients had aural toileting) Three studies compared topical antiseptics with no treatment, with one study reporting results we could use (254 children; cluster-RCT). This compared the instillation of boric acid in alcohol drops versus no ear drops for one month (both arms used daily dry mopping). We made adjustments to the data to account for the intra-cluster correlation. The very low certainty of the evidence means it is uncertain whether or not treatment with an antiseptic leads to an increase in resolution of ear discharge at both four weeks (risk ratio (RR) 1.94, 95% confidence interval (CI) 1.20 to 3.16; 174 participants) and at three to four months (RR 1.73, 95% CI 1.21 to 2.47; 180 participants). This study narratively described no differences in suspected ototoxicity or hearing outcomes between the arms (very low-certainty evidence). None of the studies reported results for health-related quality of life, adverse effects or serious complications. B. Topical antiseptic A versus topical antiseptic B Two studies compared different antiseptics but only one (93 participants), comparing a single instillation of boric acid powder with daily acetic acid ear drops, provided any information for this comparison. The very low certainty of the evidence means that it is uncertain whether more patients had resolution of ear discharge with boric acid powder compared to acetic acid at four weeks (RR 2.61, 95% CI 1.51 to 4.53; 93 participants), or whether there was a difference between the arms with respect to ear discomfort due to the low number of reported events (RR 0.10, 95% CI 0.01 to 1.81; 93 participants). Narratively, the study reported no difference in hearing outcomes between the groups. None of the included studies reported any of the other primary or secondary outcomes.

Authors' conclusions: Due to paucity of the evidence and the very low certainty of that which is available the effectiveness and safety profile of antiseptics in the treatment of CSOM is uncertain.