Efficacy of Medical Grade Manuka Honey in Acute Otitis Externa

A Pilot Study

Abstract

Introduction: 

Manuka honey has been used in chronic diabetic ulcers and traumatic wounds. We have used Manuka honey in cases of otitis externa because of its antibacterial and anti-inflammatory properties.

Objectives: 

The objective was to study the efficacy of topical applications of Manuka honey in the patients of acute otitis externa.

Materials and Methods: 

Patients with acute otitis externa without any prior ear complaint or intervention were selected for the study after informed and written consent. All patients selected for the study were packed with Manuka honey-impregnated umbilical tape and pain scores; canal wall edema was recorded on days 0, 1, 3, and 7.

Results: 

A total of 20 patients were included in our study. Twenty patients followed us on day 1, 15 patients on day 3, and seven patients followed us till day 7. The mean pain score for day 0 was 5.35, and the mean pain score decreased to 2.95 on day 1, and the difference was statistically significant.

Conclusion: 

Manuka honey appears to be an effective therapeutic agent in the management of otitis externa.

INTRODUCTION

Honey has been traditionally used as a medicinal product for various ailments because of its anti-inflammatory, antioxidant, and antibacterial properties.[¹] Honey differs in terms of its origin and constituents. Honey can be blossom, honeydew, monofloral, or polyfloral. Manuka honey is the type of monofloral honey which is derived from Leptospermum scoparium.[¹] Medical grade honey has earlier been used in the management of canine otitis externa with successful outcomes.[²] We hypothesized that the anti-inflammatory and antibiotic properties of medical-grade Manuka honey can be used in the treatment of otitis externa in human beings.

MATERIALS AND METHODS

The study was a prospective, open-label, nonblinded clinical trial. The study was conducted from November 2017 to September 2018. The clearance for this pilot study was obtained from the Institutional Ethics Committee (ECR/736/Inst/UK/2015), and the study was registered with the Clinical Trials Registry of India (CTRI/2017/11/010692). The participants were entitled to withdraw from the trial at any time and for any reason. A total of 20 cases were included in our study after informed and written consent. Inclusion criteria were patients between 12 years and 80 years of age who presented with acute otitis externa. The exclusion criteria were patient with any prior treatment or intervention or patients of chronic suppurative otitis media, chronic otitis externa, diabetes mellitus, and malignant otitis externa. Due to the possibility of the risk of ototoxicity, only patients who had an intact tympanic membrane were included in the study. All the patients with inclusion criteria and given consent were included in the study. The primary outcome observed was pain, which was measured using the pain visual analog scale (VAS) on days 0, 1, 3, and 7 (day 0 being the day of diagnosis). The secondary outcome was canal wall edema noted on days 0, 1, 3, and 7 and was assessed with serial otoendoscopy and photographs. The patient at each visit was evaluated by the same investigator to avoid interpersonal bias. Day 1 was taken as 24 h after the patient had received the intervention. The patient's ear was packed with umbilical tape (Ethicon length 18-″) impregnated with around 3–4 ml of Manuka honey gel (Medihoney gel). The Ethicon umbilical tapes are routinely used at our center due to ease of insertion, sterility and length can be tapered according to the canal size. Canal wall edema was assessed with serial endoscopic photographs and the method as described by Shrestha et al.[³] The canal was divided into four equal quadrants and assigning 25% to each quadrant, and scoring was done as per the percentage of the involvement of the canal. The patients were followed up on day 1 and day 3 to look for any adverse reaction due to Manuka honey, and wick was also changed on days 0, 1, and 3. All patients were prescribed oral analgesics and advised to take only when pain is very severe (tablet paracetamol 650 mg sos) and they were asked to report immediately. Baseline characteristics were noted, and pain scores were acquired for days 0, 1, 3, and 7 and were statistically analyzed using paired t-test.

RESULTS

The mean age of patients included in the study was 32.2 years (15–67 years). Fourteen (70%) out of 20 patients were male. According to the pain scores, patients were categorized into mild, moderate, and severe groups (mild 1–3, moderate 4–6, and severe 7–10). Ten (50%) out of 20 patients were in the moderate group, 4/20 (20%) were in the severe group, and 6/20 (30%) were in the mild group. In 12 patients, the left ear was involved, and in the rest, the right ear was involved. All 20 patients were reviewed on day 1. However, on day 3, only 15 patients (75%) had come for follow-up, and on day 7, only 7 (35%) patients had come for examination, and the rest did not come for follow-up. The telephone inquiry did not identify any case having increase in severity of pain after intervention or any adverse reaction.

The mean pain VAS score at day 0 was 5.35, and on day 1 was 2.95 after Manuka honey wick placement. The difference between pain score after the intervention was statistically significant with P < 0. 0001. On day 3, we have only 15 patients who have come up for the follow-up, and pain scores of these patients were analyzed. For these 15 patients, the mean pain score on day 1 was 3.2, and on day 3 was 1.0667. The difference was statistically significant with P < 0.0001 [Table 1]. Canal wall edema at day 1 of follow-up was resolved in 4/20 (20%) patients. Fifteen patients who visited us on day 3, five patients had complete resolution of symptoms. Seven patients who were in our follow-up till day 7 had complete resolution of symptoms with no canal wall edema [Figures 1 and 2]. None of the patients followed up on days 1, 3, and 7 had used analgesics for the pain, and no patient reported any adverse event with the use of Manuka honey.

Table 1: Patient characteristics and pain score

Figure 1: Serial otoendoscopic photograph showing complete resolution of symptoms by day 3

Figure 2: Serial otoendoscopic photograph showing complete resolution of symptoms by day 7

DISCUSSION

Acute otitis externa is a painful condition of the external auditory canal and characterized by tragal tenderness, erythema, and edema of the external auditory canal. The most common organisms associated with these conditions are Pseudomonas aeruginosa and Staphylococcus aureus. The treatment options ranged from the application of topical antibiotics to otowicks depending on the severity of the otitis externa. Quinolones and aminoglycoside antibiotic drops are commonly used in the treatment of otitis externa. The patterns of organisms and their sensitivity differ worldwide. The study of Heward et al. has shown that there is increasing resistance of P. aeruginosa to gentamicin, and this may necessitate a change in prescribing guidance.[⁴] Short-term resistance experiment performed by Cooper et al. with Manuka honey has demonstrated the absence of resistance to S. aureus, P. aeruginosa, and methicillin-resistant S. aureus. They have demonstrated the absence of resistance and have advocated the use of whole honey to prevent the development of honey resistance organisms.[⁵] This absence of resistance is possibly due to the presence of multiple compounds present in the honey.[¹]

Manuka honey is a monofloral honey, and it has been used in burn wounds, various skin conditions, and diabetic ulcers.[¹] We have used Medihoney gel (umf + 15), which has 80% of honey and has a low pH. The antibacterial activity of the Manuka honey is mainly attributed to methylglyoxal. Other compounds like defensin-1, phenolic compounds are also responsible for the antibacterial activity of the honey.[¹] Manuka honey and Cidr honey have shown to be very effective against S. aureus and P. aeruginosa biofilms, the two most common organisms isolated in otitis externa.[⁶]

Hornigold et al. have done a randomized controlled trial (RCT) comparing the ichthammol glycerol wick with topical antibiotic steroid drops. They had recruited a total of 43 patients, and the patient mean scores along all the groups were 5.6 on day 1 and decreasing to 2.3 at the second visit. In our study, the mean pain score at day 0 was 5.3 and it decreased to 2.95 on the first visit.[⁷] The mean pain score in their study and our study is comparable, and as pain is the hallmark of otitis externa, the resolution of this indicates that intervention is effective, and also none of our patients required rescue medication.

In addition to the antibacterial properties of Manuka honey, it also has anti-inflammatory properties. The healing time decreases with the use of honey, as it suppresses the production of inflammatory cells and stimulates the proinflammatory cytokines, fibroblasts, and epithelial cells.[¹] However, studies comparing Manuka honey with other standard interventions in terms of healing with respect to ear pathologies are lacking. Ichthammol glycerol wick has also been used in the management of otitis externa. The ichthammol has antibacterial, anti-inflammatory properties.[⁷] All the qualities of ichthammol glycerol are present in the Manuka honey, and both are unlikely to develop resistance. Combination of antibiotic and corticosteroid drops have shown to be more effective than antibiotics alone. This benefit is mainly attributed to the anti-inflammatory properties of steroids.[⁸] Manuka honey also has anti-inflammatory and antibiotic properties, which can possibly make it a single effective therapeutic agent in the management of otitis externa.

The alkaline pH of the external auditory canal has shown to be a local risk factor in the progression of chronic otitis externa.[⁹] Manuka honey has low pH and can inhibit the microbial growth in acute settings and inhibit protease activity in chronic wounds.[¹]

The use of ribbon gauze packing as a delivery agent for otitis externa could have better compliance, as there is no intervention required from the patient part.[⁷] In our study, we have used umbilical tape impregnated with Medihoney gel. The patient need not worry about putting drops in the ear. The use of otowicks along with standard three-time regime of topical use of antibiotics can be inappropriate treatment due to poor penetration of antibiotics, as shown by the study of Bola et al.[¹⁰] The use of umbilical tape impregnated with Manuka honey can also take care of this problem. However, our study fails to establish that whether single or multiple placements of ear wicks are required for the successful outcome, as we have changed the wick on days 0, 1, and 3.

Ear safety is a concern with the use of Manuka honey, the animal study of topical application of Manuka honey to the middle ear has been done by Aron et al. The Manuka honey in the concentration of 50% has shown to be toxic to the middle ear and inner ear, but 4% of concentration did not reveal any ototoxicity.[¹¹] For these reasons, we have not taken any patient with tympanic membrane perforation middle ear disease. Only those patients with acute onset and no previous ear problem history and intact tympanic membrane were taken for the study.

There are a lot of limitations with our pilot study, the most important being our small sample size, and a large number of patients who are lost to follow-up on day 7. We have not done culture in our study, which could have added more to the strength of our study. Another limitation of our study is that it lacks randomization with a lack of control treatment. In our study, we have evaluated the patient on day 1 and day 3 to look for any adverse reaction. In standard treatment, the patient is called once a week, and the present study did not explore the efficacy of single wick placement, therefore, we cannot comment whether single wick placement with Manuka honey will be as good as conventional treatment.

However, the initial positive experience within the setting of a pilot study suggests that Manuka honey deserves more rigorous evaluation in a large-scale RCT.

CONCLUSION

Manuka honey, because of its antibacterial properties and anti-inflammatory activity, can be used as a potential therapeutic agent in the treatment of otitis externa and can be used without worrying about local sensitivity patterns.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.