Topical treatment of acute otitis externa: clinical comparison of an antibiotics ointment alone or in combination with hydrocortisone acetate

Biomedical application of materials for external auditory canal: History, challenges, and clinical prospects

Biomaterials play an integral role in treatment of external auditory canal (EAC) diseases. Regarding the special anatomic structure and physiological characteristics of EAC, careful selection of applicable biomaterials was essential step towards effective management of EAC conditions. The bioactive materials can provide reasonable biocompatibility, reduce risk of host pro-inflammatory response and immune rejection, and promote the healing process. In therapeutic procedure, biomaterials were employed for covering or packing the wound, protection of the damaged tissue, and maintaining of normal structures and functions of the EAC. Therefore, understanding and application of biomaterials was key to obtaining great rehabilitation in therapy of EAC diseases. In clinical practice, biomaterials were recognized as an important part in the treatment of different EAC diseases. The choice of biomaterials was distinct according to the requirements of various diseases. As a result, awareness of property regarding different biomaterials was fundamental for appropriate selection of therapeutic substances in different EAC diseases. In this review, we firstly introduced the characteristics of EAC structures and physiology, and EAC pathologies were summarized secondarily. From the viewpoint of biomaterials, the different materials applied to individual diseases were outlined in categories. Besides, the underlying future of therapeutic EAC biomaterials was discussed.

Otitis Externa

BACKGROUND

Otitis externa has a lifetime prevalence of 10% and can arise in acute, chronic, and necrotizing forms.

METHODS

This review is based on publications retrieved by a selective search of the pertinent literature.

RESULTS

The treatment of acute otitis media consists of anal- gesia, cleansing of the external auditory canal, and the appli- cation of antiseptic and antimicrobial agents. Local antibiotic and corticosteroid preparations have been found useful, but there have been no large-scale randomized controlled trials of their use. Topical antimicrobial treatments lead to a higher cure rate than placebo, and corticosteroid preparations lessen swelling, erythema, and secretions. Oral antibiotics are indi- cated if the infection has spread beyond the ear canal or in patients with poorly controlled diabetes mellitus or immuno- suppression. Chronic otitis externa is often due to an under- lying skin disease. Malignant otitis externa, a destructive infection of the external auditory canal in which there is also osteomyelitis of the petrous bone, arises mainly in elderly diabetic or immunosuppressed patients and can be life- threatening.

CONCLUSION

With correct assessment of the different types of otitis externa, rapidly effective targeted treatment can be initi- ated, so that complications will be avoided and fewer cases will progress to chronic disease.

Fingerprint Spectrophotometric Methods for the Determination of Co-Formulated Otic Solution of Ciprofloxacin and Fluocinolone Acetonide in Their Challengeable Ratio

Six spectrophotometric methods were developed to determine a new single-dose otic solution known as "Otovel®," which consists of two components: the major one is ciprofloxacin (CIP) and the minor is fluocinolone acetonide (FLU). The ratio of (CIP) and (FLU) in Otovel® is 12 : 1, which is considered a challengeable ratio for UV determination. Thus, spectrum addition as a sample enrichment technique was required for the analysis of (FLU) low concentration. All these methods were capable of resolving the spectra for each component in D 0 belonging to the fingerprint resolution technique. The former absorptivity centering (a-centering) method was recently developed in 2018; it was effectively applied for its solution of both binary components in Otovel®, while another method, ratio subtraction (RS), is considered as an original resolution method that could be applied to determine only one component in mixtures. However, the other four methods that are related to their original method (RS) were extended ratio subtraction (EXRS), constant multiplication (CM), unified constant subtraction (UCS), and spectrum subtraction (SS). They were also easily applied for completing the quantification of binary mixture drugs present in Otovel®. The linearity ranges were found to be 3.0-15.0 μg/mL for (CIP) and (FLU), respectively. All results acquired from the proposed methods were successfully estimated according to ICH criteria and were statistically compared with official ones where no differences were noticed.

Topical antimicrobial therapy: Current status and challenges

Topically applied antibacterial agents are widely used. Opinions regarding the clinical efficacy of topical antibiotics are conflicting, and for most indications, alternative oral therapies are available. Topical application has many potential advantages over systemic therapy that includes high and sustained concentrations of drug directly at the infected site, low quantity of antibiotic needed, better compliance, fewer systemic side effects and potentially less chance of antimicrobial resistance. Despite these advantages, an important concern has been the difficulty in monitoring antibiotic dosage and duration of therapy. Most topical preparations are applied on sites with pre-existing normal bacterial flora, and the detrimental effect of antibiotic on the 'good' bacteria is difficult to control. Unnecessary exposure of the resident microflora to high drug levels may select drug-resistant phenotypes. The number of antibiotics available and the quality and composition of the formulations recommended for topical drug delivery are improving. Their role in the prevention and treatment of locally invasive infections is established for many clinical conditions. However, there is still a lacuna in the availability of pharmacokinetic (PK) knowledge of these topical preparations and translation of the same to clinical practice. In addition, reporting the clinical outcome following the use of these agents and its analysis considering the recently proposed epidemiological cut-off value-based cut-offs are also areas which merit further research. In this review, we highlight the clinical utility and the PK aspects of topical antimicrobials in various infections. We also discuss the limitations of the current antimicrobial susceptibility testing (AST) protocols and new methods for AMST for topical agents.

Acute otitis externa

Acute otitis externa, also known as 'swimmer's ear', is a common disease of children, adolescents and adults. While chronic suppurative otitis media or acute otitis media with tympanostomy tubes or a perforation can cause acute otitis externa, both the infecting organisms and management protocol are different. This practice point focuses solely on managing acute otitis externa, without acute otitis media, tympanostomy tubes or a perforation being present.

A meta-analysis of the efficacy of quinolone containing otics in comparison to antibiotic-steroid combination drugs in the local treatment of otitis externa

BACKGROUND

The term otitis externa denotes the inflammation of the external auditory canal and can be treated locally in the form of monotherapy or a combination drug.

OBJECTIVE

The aim of the present meta-analysis was to compare the efficacy of an antibiotic-steroid combination drug with that of monotherapy. According to current data, a comparable investigation based on network analysis does not exist.

METHODS

After systematically searching the PubMed, Medline, Medpilot, Web of Science and Embase electronic databases, 12 relevant randomized, controlled, clinical studies were identified involving 2682 evaluable patients with regard to the cure rate and seven publications with 1251 microbiologically assessable patients. The collected data were compared directly and indirectly by means of network analysis.

RESULTS

The direct comparison showed a trend towards the superiority of the monotherapy containing quinolone. The network analysis verified this tendency and demonstrated that pure quinolone drugs can achieve a significantly higher cure rate (OR: 1.29; 95% CI: 1.06-1.57; p = 0.01) and a significantly superior eradication rate (OR: 1.44; 95% CI: 1.03-2.02; p = 0.03) compared to combination drugs not containing quinolone. We found substantial heterogeneity (with I(2) up to 88.7%) between studies, presumably due to treatments applied in varying frequency, thus bearing on compliance and outcome.

CONCLUSION

With a level Ia evidence, this investigation validates the clinical benefit of quinolones as compared to classic combination drugs in the local treatment of acute otitis externa.

Interventions for acute otitis externa

BACKGROUND

Acute otitis externa is an inflammatory condition of the ear canal, with or without infection. Symptoms include ear discomfort, itchiness, discharge and impaired hearing. It is also known as 'swimmer's ear' and can usually be treated successfully with a course of ear drops.

OBJECTIVES

To assess the effectiveness of interventions for acute otitis externa.

SEARCH STRATEGY

Our search for published and unpublished trials included the Cochrane Ear, Nose and Throat Disorders Group Trials Register; CENTRAL; PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; mRCT and additional sources. The date of the most recent search was 6 January 2009.

SELECTION CRITERIA

Randomised controlled trials evaluating ear cleaning, topical medication or systemic therapy in the treatment of acute otitis externa were eligible.We excluded complicated acute otitis externa; otitis externa secondary to otitis media or chronic suppurative otitis media; chronic otitis externa; fungal otitis externa (otomycosis); eczematous otitis externa; viral otitis externa and furunculosis.

DATA COLLECTION AND ANALYSIS

Two authors assessed eligibility and quality.

MAIN RESULTS

Nineteen randomised controlled trials with a total of 3382 participants were included. Three meta-analyses were possible. The overall quality of studies was low.Topical antimicrobials containing steroids were significantly more effective than placebo drops: OR 11 (95% CI 2.00 to 60.57; one trial).In general, no clinically meaningful differences were noted in clinical cure rates between the various topical interventions reviewed. One notable exception involved a trial of high quality which showed that acetic acid was significantly less effective when compared with antibiotic/steroid drops in terms of cure rate at two and three weeks (OR 0.29 (95% CI 0.13 to 0.62) and OR 0.25 (95% CI 0.11 to 0.58) respectively).One trial of low quality comparing quinolone with non-quinolone antibiotics did not find any difference in clinical cure rate.No trials evaluated the effectiveness of ear cleaning.Only two trials evaluated steroid-only drops. One trial of low quality suggested no significant difference between steroid and antibiotic/steroid but did not report the magnitude or precision of the result. Another trial of moderate quality comparing an oral antihistamine with topical steroid against topical steroid alone found that cure rates in both groups were high and comparable (100% (15/15) and 94% (14/15) respectively at three weeks).

AUTHORS' CONCLUSIONS

There is a paucity of high quality trials evaluating interventions for acute otitis externa. The results of this systematic review are largely based on odds ratios calculated from single trials, most of which have very broad 95% confidence intervals because of small to modest sample sizes. The findings may not be wholly generalisable to primary care for a variety of reasons; only two of the 19 trials included in the review were conducted in a primary care population setting, and in 11 of the 19 trials ear cleaning formed part of the treatment (an intervention unlikely to be available in primary care). Despite these reservations, some meaningful conclusions can be drawn from the evidence available:Topical treatments alone, as distinct from systemic ones, are effective for uncomplicated acute otitis externa. In most cases the choice of topical intervention does not appear to influence the therapeutic outcome significantly. Any observed differences in efficacy were usually minor and not consistently present at each follow-up visit. Acetic acid was effective and comparable to antibiotic/steroid at week 1. However, when treatment needed to be extended beyond this point it was less effective. In addition, patient symptoms lasted two days longer in the acetic acid group compared to antibiotic/steroid.The evidence for steroid-only drops is very limited and as yet not robust enough to allow us to reach a conclusion or provide recommendations. Further investigation is needed.Given that most topical treatments are equally effective, it would appear that in most cases the preferred choice of topical treatment may be determined by other factors, such as risk of ototoxicity, risk of contact sensitivity, risk of developing resistance, availability, cost and dosing schedule. Factors such as speed of healing and pain relief are yet to be determined for many topical treatments and may also influence this decision.Patients prescribed antibiotic/steroid drops can expect their symptoms to last for approximately six days after treatment has begun. Although patients are usually treated with topical medication for seven to 10 days it is apparent that this will undertreat some patients and overtreat others. It may be more useful when prescribing ear drops to instruct patients to use them for at least a week. If they have symptoms beyond the first week they should continue the drops until their symptoms resolve (and possibly for a few days after), for a maximum of a further seven days. Patients with persisting symptoms beyond two weeks should be considered treatment failures and alternative management initiated.

Dexamethasone phosphate in antibiotic ear drops for the treatment of acute bacterial otitis externa

OBJECTIVES

To compare the efficacy and safety of polymyxin sulfate 7500 IU/neomycin sulfate 3500 IU/dexamethasone phosphate 0.1% (PN+Dx) otic solution with polymyxin sulfate 7500 IU/neomycin sulfate 3500 IU (PN-Dx) in patients with acute bacterial otitis externa (AOE), in order to determine the possible benefit of the addition of dexamethasone.

RESEARCH DESIGN AND METHODS

Active controlled, double-blind, randomized, parallel group, multi-center clinical trial in ear, nose, and throat (ENT) specialist practices with a planned interim analysis for sample size adaptation. In total, 338 patients aged 18-76 who had a previous episode of otitis externa within the last year were randomized to receive 10 +/- 2 days of treatment with two drops, three times daily, of either PN+Dx or PN-Dx.

MAIN OUTCOME MEASURES

Change in the clinical symptom score (consisting of the subscores redness, swelling, pain, and secretion) and of the visual analogue scale (VAS) rating for pain from Visit 1 (Day 1) to Visit 2 (Day 4 +/- 1), patient's assessment of efficacy at Visit 3 (Day 10 +/- 2), and the frequency and type of adverse events.

RESULTS

There was a significantly greater reduction of swelling from Visit 1 to Visit 2 with PN+Dx, and more patients rated the efficacy of PN+Dx as 'very good' or 'good' at Visit 3 (p = 0.03). There was also a significantly greater decrease in the clinical symptom score from Visit 1 to Visit 2 in the PN+Dx group in patients who had at least a moderately severe symptom score with more than seven points at Visit 1 (p = 0.01) and in patients suffering from their current episode of otitis externa for more than 2 days (p = 0.02). In total, 14 adverse events were reported during the study period with no related adverse drug reactions for PN+Dx.

CONCLUSIONS

The addition of dexamethasone phosphate to polymyxin B/neomycin significantly reduces swelling in patients with AOE and leads to significantly higher patient's ratings of treatment efficacy. It especially leads to an overall reduction of symptoms in cases of moderately or more severe otitis externa and cases lasting for more than 2 days.