Introduction
Acute otitis externa is a disease characterised by diffuse or localised inflammation of the external auditory canal, which may cause otalgia, itching and fullness, with or without hearing loss. Signs of ear canal inflammation include tenderness of the tragus and/or pinna, otorrhoea, and erythema. A diagnosis of acute otitis externa requires rapid onset of these symptoms and signs within the previous three weeks (generally within 48 hours).Reference Bojrab, Bruderly and Abdulrazzak1, Reference Rosenfeld, Schwartz, Cannon, Roland, Simon and Kumar2 It is a common condition, affecting 5–20 per cent of all patients encountered in otolaryngological practice.Reference Hawke, Wong and Krajden3
The aetiology and development of acute otitis externa have been discussed previously, and four aetiological subgroups have been defined to elucidate a condition that is often multifactorial.Reference Peterkin4 Genetic, environmental, traumatic and infective factors may be responsible for the pathogenesis of acute otitis externa. The two most common isolates associated with acute otitis externa are Pseudomonas aeruginosa and Staphylococcus aureus, followed by Gram-negative bacteria, and fungal pathogens such as aspergillus and candida species.Reference Rosenfeld, Schwartz, Cannon, Roland, Simon and Kumar2, Reference Schaefer and Baugh5
For effective treatment of severe acute otitis externa, topical medication must reach the site of infection. To achieve this goal, it is important that clinicians clean the external auditory canal if it is blocked by debris or a foreign body, and place packing in the external auditory canal. When there is prominent, severe acute otitis externa, packing, such as a wick or ribbon gauze, may facilitate the delivery of topical medication and reduce oedema. An ear wick made of compressed cellulose can expand in the external auditory canal when exposed to moisture. Alternatively, ribbon gauze can be used in the treatment of severe acute otitis externa.Reference Rosenfeld, Schwartz, Cannon, Roland, Simon and Kumar2, Reference Pond, McCarty and O'Leary6
Biodegradable synthetic polyurethane foam is produced by a freeze-drying process. It absorbs water, while supporting the surrounding tissue. Its clinical efficacy in terms of improving subjective symptoms has been investigated in many nasal surgery studies.Reference Wang, Cai and Wang7, Reference Lorente, Sabater, Rivas, Fuste, Risco and Gómez8 However, to the best of our knowledge, an evaluation of biodegradable synthetic polyurethane foam in patients with acute otitis externa has not previously been reported in the English-language literature. Therefore, the present study aimed to investigate the utility of biodegradable synthetic polyurethane foam in patients with severe acute otitis externa by comparing it with ear wick and ribbon gauze as packing media in terms of patient comfort and efficiency.
Materials and methods
Ninety-two consecutive patients with severe acute otitis externa were enrolled in this prospective randomised study in the Department of Otolaryngology of Sakarya University Medical Faculty, Turkey, between May 2015 and August 2017. Written informed consent was obtained from each patient after discussing the full details of the surgical procedure and the underlying aim. This study was approved by the Sakarya University Local Ethical Committee.
Enrolment of patients was based on the clinical features of acute otitis externa, which included otalgia, pinna or tragal tenderness, erythema, and the presence of an occluded external auditory canal. Patients were excluded if they were younger than 18 years, had diabetes, serious underlying disease, possible otomycosis, immunosuppressive disorders, congenital or obstructive pathologies of the external auditory canal, a tympanic membrane perforation, spread of infection beyond the external auditory canal, or symptoms that had persisted longer than 2 weeks. Data on age, gender, exposure to water, use of cotton buds and hearing aids, and aural dermatitis were collected.
Samples for bacterial culture were taken on the first visit before treatment. Aural toilet was then gently performed with an ear swab of the affected ear for each patient. Patients were subsequently randomised into three packing groups using a block randomisation method (Figure 1). The packing materials inserted in these groups were: ear wick (Merocel Pope Ear Wick, 1.5 cm length; Medtronic Xomed, Jacksonville, Florida, USA), biodegradable synthetic polyurethane foam (OtoPore Ear Cylinder (standard, firm), 2 cm length; Polyganics, Groningen, the Netherlands), or a strip of ribbon gauze (10 cm length).
Flow diagram of patients included in the study. BSPF = biodegradable synthetic polyurethane foam.
Before packing was applied, scores for otalgia and relevant signs, including oedema, erythema and tenderness of the external auditory canal, were assessed. The patients were asked to grade their otalgia severity on a 10-point visual analogue scale (VAS), where 0 denoted no otalgia and 10 represented the most severe otalgia felt. We also used scales to evaluate: oedema, graded as 0 (absent), 1 (oedema of less than 50 per cent) or 2 (oedema of more than 50 per cent); erythema, graded as 0 (absent) or 1 (present); and tenderness, graded as 0 (absent) or 1 (present).
The packing was left in the external auditory canal for 48 hours only, as a prophylactic measure against toxic shock syndrome. Patients were reassessed on the 3rd and 7th days of presentation by the same author. All patients received the same medications: an oral analgesic (paracetamol) 2 times daily, 3 drops of topical antimicrobial (ciprofloxacin) 3 times daily, and 3 drops of topical corticosteroid (dexamethasone) 3 times daily for 7 days, to avoid bias. All patients were asked to have another person administer the ear drops, who was taught to properly apply the drops. Patients were evaluated in the early morning, before any analgesics were taken, so that otalgia scores were not affected by medication.
Statistical analysis
Descriptive analyses were performed to provide information on general characteristics of the study population. The Kolmogorov–Smirnov test was used to evaluate whether the distribution of continuous variables was normal. The Kruskal–Wallis H test was used for the comparison of VAS scores among the three groups. The Friedman test was used to analyse the VAS scores in the three time periods (the Bonferroni test was used for post-hoc comparisons between the pairs of follow-up periods). Continuous variables are presented as means ± standard deviations. Categorical variables were compared among the three groups using chi-square tests. The Cochran Q test was used to analyse tenderness and erythema for the three time periods (the Bonferroni adjusted McNemar test was used for post-hoc comparisons between the pairs of follow-up periods). Kendall's W test was used to analyse oedema in the three time periods (the Bonferroni adjusted marginal homogeneity test was used for post-hoc comparisons between the pairs of follow-up periods). Categorical variables are presented as count and percentage. A p-value of less than 0.05 was considered significant. Analyses were performed using SPSS Statistics software, version 23.0 (IBM, Armonk, New York, USA).
Results
Of 96 patients, 92 were enrolled in this study; 4 patients were lost to follow up. The patients were randomly assigned to: the ear wick group (n = 28), ribbon gauze group (n = 34) or biodegradable synthetic polyurethane foam group (n = 30) (Figure 1). The post-hoc statistical power was calculated as more than 0.90 according to present results (using PASS 13 power and sample size software; NCSS Statistical Software, Kaysville, Utah, USA).
Age and gender distributions were similar among the groups (p = 0.827 and p = 0.809 respectively) (Table I). Additionally, there were no differences in the distribution of aetiological factors and systemic diseases in these groups.
Comparison of patients’ characteristics and aetiological factors among groups
* n = 28;
† n = 34;
‡ n = 30.
BSPF = biodegradable synthetic polyurethane foam;
SD = standard deviation
The frequency distribution of bacteria among the three groups was not significantly different (p = 0.758) (Table II). A mixed growth of P aeruginosa and S aureus was isolated from one patient in the ribbon gauze group. Twenty-three patients (25 per cent) from all groups had no growth of any organism.
Frequency distribution of bacteria in the three groups
Data represent numbers (and percentages), unless indicated otherwise.
* n = 28;
† n = 34;
‡ n = 30.
BSPF = biodegradable synthetic polyurethane foam
All patients were cured by the end of follow up. No adverse effects or complications occurred.
In terms of average otalgia scores, there was a statistically significant difference between biodegradable synthetic polyurethane foam and the other packing materials on the 3rd day (p < 0.001), but not on the 1st or 7th days (p = 0.532 and p = 0.757 respectively). However, statistically significant differences between the 1st and 3rd days and between the 3rd and 7th days were detected in all groups (p < 0.001) (Figure 2 and Table III).
Comparison of otalgia at all time periods among the three groups. CI = confidence interval; VAS = visual analogue scale; BSPF = biodegradable synthetic polyurethane foam.
Comparison of otalgia among groups
Data are shown as mean scores ± standard deviations, unless indicated otherwise.
* n = 28;
† n = 34;
‡ n = 30.
** Indicates statistically significant differences between biodegradable synthetic polyurethane foam and the other packing materials.
§ Indicates statistically significant differences between all pairwise comparisons (time periods).
BSPF = biodegradable synthetic polyurethane foam
With regard to tenderness, there were statistically significant differences in scores for the biodegradable synthetic polyurethane foam group between the 1st and 7th days and between the 3rd and 7th days (p < 0.001); no significant differences were observed between the 1st and 3rd days. Tenderness scores were significantly different for the ear wick and ribbon gauze groups compared to the biodegradable synthetic polyurethane foam group at both the 3rd and 7th days (p < 0.001) (Table IV).
Comparison of acute otitis externa signs among groups
Data represent numbers (and percentages), unless indicated otherwise.
* n = 28;
† n = 34;
‡ n = 30.
** Indicates statistically significant differences between all pairwise comparisons.
§ Indicates statistically significant differences between the 7th day and other time periods.
BSPF = biodegradable synthetic polyurethane foam
As shown in Table IV, there were significant differences in oedema for all groups between the 1st and 3rd days, and between the 3rd and 7th days (p < 0.001). However, on the 3rd day, ear wick and ribbon gauze were superior to biodegradable synthetic polyurethane foam with regard to relieving oedema (p = 0.022). There was a statistically significant decrease in erythema on both the second and third visits for all groups (p < 0.001).
Discussion
Acute otitis externa, also called swimmer’s ear, is diagnosed clinically based on signs and symptoms relating to external auditory canal inflammation. Otalgia is one of the major symptoms of acute otitis externa. Lorente et al. showed that the most frequent symptoms found at baseline among 545 patients randomly assigned to 1 of 2 treatment groups were: otalgia (98 per cent for the first group and 98.6 per cent for the second group), otorrhoea (80.4 per cent and 85.4 per cent), oedema (74.7 per cent and 75.5 per cent) and hypoacusis (70.6 per cent and 69.4 per cent).Reference Lorente, Sabater, Rivas, Fuste, Risco and Gómez8 In our study, whereas otalgia and oedema were major complaints at baseline for all patients, tenderness and erythema were observed in 95.6 per cent and 90.2 per cent, respectively, at baseline. However, because oedema was defined as an inclusion criterion in the present study, its incidence cannot be accurately evaluated.
Signs and symptoms correlate with the severity of inflammation affecting the periosteal lining of the bony canal, and so the main goal of treatment is to control inflammation. Meticulous cleaning of the external auditory canal with atraumatic instruments should be a priority because topical medications rely on direct contact with the infected skin of the external auditory canal.Reference Schaefer and Baugh5, Reference Linstrom, Lucento, Joseph and Bailey9 Moreover, topical medications sometimes cannot reach all of the external auditory canal. In cases of severe acute otitis externa, the key to topical treatment is to place packing in the ear canal, in order to facilitate delivery of topical medication. Only a few studies have examined the efficacy of packing in the treatment of severe acute otitis externa.Reference Pond, McCarty and O'Leary6, Reference Barr and al-Khabori10 Furthermore, there are no data available regarding the use of biodegradable synthetic polyurethane foam, a new absorbable packing material, in treatment of severe acute otitis externa as an ear packing material.
In the present study, the efficacy and utility of three ear packing materials were evaluated by comparing the changes in otalgia, oedema, erythema and tenderness scores. Our study indicates that the three packing materials are quite effective in treating acute otitis externa. However, in terms of all scores, the ear wick and ribbon gauze were superior. When using the packing, almost all scores had significantly decreased on the 3rd day (p < 0.001). At that point, there were significant improvements in otalgia, oedema and erythema for all groups; however, there was no significant reduction in tenderness for the biodegradable synthetic polyurethane foam group. Moreover, at the 3rd day, the ear wick and ribbon gauze were superior to biodegradable synthetic polyurethane foam with regard to relieving oedema and otalgia.
Pond et al. studied the efficacy of ear wick and ribbon gauze in terms of the total number of out-patient visits, and the resolution of acute otitis externa as defined by the absence of otalgia and otorrhoea and by improvement in hearing.Reference Pond, McCarty and O'Leary6 In that study, ribbon gauze treatment achieved a similar resolution rate to that of the ear wick, but was associated with fewer out-patient visits. Although biochemically similar, the authors did not use the same medication for the two groups. Hence, their method may have introduced bias.
We believe that ear wick and ribbon gauze are more effective than biodegradable synthetic polyurethane foam at the 3rd day, possibly because of their expansile properties. Ear wick and ribbon gauze could provide more pressure to the ear canal wall than biodegradable synthetic polyurethane foam. Therefore, these materials better distribute the medication to the epithelial tissue lining of the external auditory canal and absorb ear discharge.
The dissolvable property of biodegradable synthetic polyurethane foam means that it does not require removal from the external auditory canal. This could be advantageous in the treatment of severe acute otitis externa in terms of decreasing the number of visits; however, we did not consider this property because the packing needed to be removed on the 3rd day.
Topical medication for acute otitis externa includes antibiotics, with or without topical corticosteroids, and antiseptics, which are mainly used to reduce inflammation of the external auditory canal. According to a systematic review published in 2010, there are 26 different preparations or combinations of topical agents for treating acute otitis externa.Reference Kaushik, Malik and Saeed11 Topical antimicrobials are highly effective compared with placebo, and the choice of antimicrobials has a minimal impact on clinical and bacteriological cure rates.Reference Rosenfeld, Singer, Wasserman and Stinnett12 The use of aminoglycosides, quinolones, polymyxin B and acetic acid is commonly reported in the literature. Overall, the evidence does not indicate that any agent or preparation is more effective than another.Reference Schaefer and Baugh5, Reference Kaushik, Malik and Saeed11, Reference Rosenfeld, Singer, Wasserman and Stinnett12
The efficacy of some combination drops has been demonstrated. The combination of steroids and antimicrobial agents is frequently used because of their different effects, such as the anti-inflammatory effect of steroids, which results in better control of acute otitis externa signs. The antibiotic and steroid combination improves clinical efficacy and bacteriological response compared to the administration of antibiotics alone.Reference Lorente, Sabater, Rivas, Fuste, Risco and Gómez8 Interestingly, both clinical and experimental studies show that a steroid solution used alone is more effective than a steroid and antibiotic combination in terms of curing acute otitis externa.Reference Emgård and Hellström13, Reference Emgård and Hellström14
In cases of severe acute otitis externa, the expansile property of packing can facilitate delivery of topical medication and reduce oedema. The authors of an in vitro study recommend that only aqueous ear drops are prescribed when using expandable ear packing, for maximum expansile effectiveness.Reference Clamp15 In our study, we preferred to add a steroid agent to the antibiotic agent because of the presence of severe oedema.
Several factors have been put forward to explain the development of acute otitis externa. Among the host factors are canal stenosis, exostoses, hairy ear canals, type A blood group, and dermatological conditions such as psoriasis and dermatitis. Acute otitis externa may also be associated with environmental risk factors including water exposure, humidity, earplugs and hearing aids.Reference Schaefer and Baugh5 In some studies, it has been reported that acute otitis externa is more common in regions with warmer climates, increased humidity or increased water exposure from swimming.Reference Russell, Donnelly, McShane, Alun-Jones and Walsh16–Reference Masood, Moumoulidis, Ray, Chawla and Panesar18 This is consistent with our findings which showed that water exposure was the most common predisposing factor. In our study, the predisposing factors of water exposure, use of cotton buds or hearing aids, dermatological conditions, and unknown variables accounted for 58 per cent, 19 per cent, 13 per cent and 10 per cent of cases, respectively.
In earlier studies, P aeruginosa was found to be the predominant micro-organism (37.7 per cent in Roland and Stroman;Reference Roland and Stroman19 45.1 per cent in Ninkovic et al.Reference Ninkovic, Dullo and Saunders20) and staphylococcal species were the second most frequently isolated organisms.Reference Roland and Stroman19, Reference Ninkovic, Dullo and Saunders20 When commencing acute otitis externa treatment, the use of topical medication without bacterial culture analysis can be an acceptable approach for patients with mild symptoms. However, in cases of resistant disease or recurrence, culture analysis is required. In the present study, no treatment failure or complication occurred, and P aeruginosa and S aureus accounted for 63 per cent and 8 per cent, respectively, of the total number of recurrences.
• Acute otitis externa is characterised by external auditory canal inflammation, causing otalgia, itching and fullness, with or without hearing loss
• Packing in the external auditory canal is required for effective treatment of severe acute otitis externa
• Ear wick and ribbon gauze were superior to biodegradable synthetic polyurethane foam in relieving signs and symptoms, especially on day 3
Removal of packing can be time-consuming and troublesome. In this regard, biodegradable synthetic polyurethane foam has advantages, including biodegradability, ease of manipulation and no need for removal. In terms of the cost effectiveness of packing, although biodegradable synthetic polyurethane foam improves patient comfort, it is much more expensive (almost $18) compared with ear wick and ribbon gauze. Ribbon gauze is much cheaper ($0.02 per 10 cm strip) than the other packing materials. An ear wick costs approximately $3.50.
Conclusion
The three packing materials were effective in relieving the acute otitis externa signs and symptoms assessed. However, on the second visit, ear wick and ribbon gauze achieved significantly better otalgia and oedema control than biodegradable synthetic polyurethane foam, and there was no significant improvement in tenderness scores for the biodegradable synthetic polyurethane foam group at that time.
Competing interests
None declared.
