Background
Build up of ear wax is common. It can be uncomfortable for the patient and can cause hearing problems. Ear drops have been studied as a potential tool to soften the wax, preventing the need for further treatment such as syringing. This review looks at which treatment (oil- and water-based drops or sprays) can help resolve wax build up.
Study characteristics
In March 2018 we searched for clinical trials where ear drops were used to help soften and remove build up of ear wax in patients' ears. We found and included 10 studies with a total of 623 participants. However, only six of these studies provided data with which we could analyse our primary outcome, the proportion of patients with complete ear wax clearance. These six studies included a total of 360 participants, both children and adults (of all ages), with partial or full blockage of the external ear canal with ear wax.
Key results
The 10 included studies looked at either oil-based drops (triethanolamine polypeptide, almond oil, benzocaine, chlorobutanol), water-based drops (docusate sodium, carbamide peroxide, phenazone, choline salicylate, urea peroxide, potassium carbonate), saline (salty water) or water alone, or no treatment.
Only one study compared using drops with an active ingredient to not using drops at all. The drops may help increase the proportion of ears cleared of wax from 1 in 20 (if you do nothing) to about 1 in 5 (if you use drops).
We did not find any evidence that water-based or oil-based drops were any different to saline or water. However, we also did not find any evidence that water or saline were better than doing nothing.
Adverse (side) effects were not common. Fewer than 30 patients reported any adverse events when using the drops and these were mild (such as slight irritation or pain, or unpleasant smell). No serious side effects were reported by any participant.
Quality of the evidence
We rated the quality of the evidence from studies using four levels: very low, low, moderate or high quality. High-quality evidence means that we are very confident in the results. Very low-quality evidence means that we are very uncertain about the results. For wax clearance, we rated the quality of the evidence as low. For adverse effects we rated the quality of the evidence as low.
Conclusions
We have found that using ear drops when you have a partially or completely blocked ear canal may help to remove the ear wax in your ear. It is not clear whether one type of drop is any better than another, or whether drops containing active ingredients are any better than plain or salty water.
Although a number of studies aimed to evaluate whether or not one type of cerumenolytic is more effective than another, there is no high-quality evidence to allow a firm conclusion to be drawn and the answer remains uncertain.
A single study suggests that applying ear drops for five days may result in a greater likelihood of complete wax clearance than no treatment at all. However, we cannot conclude whether one type of active treatment is more effective than another and there was no evidence of a difference in efficacy between oil-based and water-based active treatments.
There is no evidence to show that using saline or water alone is better or worse than commercially produced cerumenolytics. Equally, there is also no evidence to show that using saline or water alone is better than no treatment.
Ear wax (cerumen) is a normal bodily secretion that can become a problem when it obstructs the ear canal. Symptoms attributed to wax (such as deafness and pain) are among the commonest reasons for patients to present to primary care with ear trouble.
Wax is part of the ear's self-cleaning mechanism and is usually naturally expelled from the ear canal without causing problems. When this mechanism fails, wax is retained in the canal and may become impacted; interventions to encourage its removal may then be needed. Application of ear drops is one of these methods. Liquids used to remove and soften wax are of several kinds: oil-based compounds (e.g. olive or almond oil); water-based compounds (e.g. sodium bicarbonate or water itself); a combination of the above or non-water, non-oil-based solutions, such as carbamide peroxide (a hydrogen peroxide-urea compound) and glycerol.
To assess the effects of ear drops (or sprays) to remove or aid the removal of ear wax in adults and children.
We searched the Cochrane ENT Trials Register; Cochrane Register of Studies; PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 23 March 2018.
Randomised controlled trials (RCTs) in which a 'cerumenolytic' was compared with no treatment, water or saline, an alternative liquid treatment (oil or almond oil) or another 'cerumenolytic' in adults or children with obstructing or impacted ear wax.
We used the standard methodological procedures expected by Cochrane. The primary outcomes were 1) the proportion of patients (or ears) with complete clearance of ear wax and 2) adverse effects (discomfort, irritation or pain). Secondary outcomes were: extent of wax clearance; proportion of people (or ears) with relief of symptoms due to wax; proportion of people (or ears) requiring further intervention to remove wax; success of mechanical removal of residual wax following treatment; any other adverse effects recorded and cost. We used GRADE to assess the quality of the evidence for each outcome; this is indicated in italics.
We included 10 studies, with 623 participants (900 ears). Interventions included: oil-based treatments (triethanolamine polypeptide, almond oil, benzocaine, chlorobutanol), water-based treatments (docusate sodium, carbamide peroxide, phenazone, choline salicylate, urea peroxide, potassium carbonate), other active comparators (e.g. saline or water alone) and no treatment. Nine of the studies were more than 15 years old.
The overall risk of bias across the 10 included studies was low or unclear.
Primary outcome: proportion of patients (or ears) with complete clearance of ear wax
Six studies (360 participants; 491 ears) contributed quantitative data and were included in our meta-analyses.
Active treatment versus no treatment
Only one study addressed this comparison. The proportion of ears with complete clearance of ear wax was higher in the active treatment group (22%) compared with the no treatment group (5%) after five days of treatment (risk ratio (RR) 4.09, 95% confidence interval (CI) 1.00 to 16.80); one study; 117 ears; NNTB = 8) (low-quality evidence).
Active treatment versus water or saline
We found no evidence of a difference in the proportion of patients (or ears) with complete clearance of ear wax when the active treatment group was compared to the water or saline group (RR 1.47, 95% CI 0.79 to 2.75; three studies; 213 participants; 257 ears) (low-quality evidence). Two studies applied drops for five days, but one study only applied the drops for 15 minutes. When we excluded this study in a sensitivity analysis it did not change the result.
Water or saline versus no treatment
This comparison was only addressed in the single study cited above (active versus no treatment) and there was no evidence of a difference in the proportion of ears with complete wax clearance when comparing water or saline with no treatment after five days of treatment (RR 4.00, 95% CI 0.91 to 17.62; one study; 76 ears) (low-quality evidence).
Active treatment A versus active treatment B
Several single studies evaluated 'head-to-head' comparisons between two active treatments. We found no evidence to show that one was superior to any other.
Subgroup analysis of oil-based active treatments versus non-oil based active treatments
We found no evidence of a difference in this outcome when oil-based treatments were compared with non-oil-based active treatments.
Primary outcome: adverse effects: discomfort, irritation or pain
Only seven studies planned to measure and did report this outcome. Only two (141 participants; 176 ears) provided useable data. There was no evidence of a significant difference in the number of adverse effects between the types of ear drops in these two studies. We summarised the remaining five studies narratively. All events were mild and reported in fewer than 30 participants across the seven studies (low-quality evidence).
Secondary outcomes
Three studies reported 'other' adverse effects (how many studies planned to report these is unclear). The available information was limited and included occasional reports of dizziness, unpleasant smell, tinnitus and hearing loss. No significant differences between groups were reported. There were no emergencies or serious adverse effects reported in any of the 10 studies.
There was very limited or no information available on our remaining secondary outcomes.