Acute otitis externa is a diffuse inflammatory condition of the external auditory canal that may also involve the pinna or tympanic membrane. It commonly presents with otalgia, itching, aural fullness, otorrhoea and temporary hearing impairment, with tenderness on manipulation of the tragus or pinna being a characteristic clinical sign.[1,2] The condition frequently develops after swimming, excessive moisture exposure, mechanical trauma caused by cotton buds or other objects, use of hearing devices, or disruption of the protective cerumen barrier. These factors increase the pH of the external auditory canal and damage its epithelium, thereby facilitating microbial growth.[1,3] Pseudomonas aeruginosa and Staphylococcus aureus are the organisms most commonly associated with bacterial acute otitis externa, although the infection may occasionally be polymicrobial.[2,3] Uncomplicated acute otitis externa is primarily managed with topical therapy because it delivers a high concentration of medication directly to the affected canal while minimizing systemic adverse effects.[1,4] Acetic acid produces an acidic environment that inhibits bacterial and fungal growth and helps restore the normal physiological conditions of the external auditory canal. It is inexpensive, widely available and does not contribute substantially to antimicrobial resistance. However, it may cause transient burning or irritation and may provide slower symptomatic relief when canal inflammation is marked.[3,5] Steroid–antibiotic ear drops combine the antimicrobial activity of an antibiotic with the anti-inflammatory action of a corticosteroid. The steroid component may produce faster reduction in canal oedema, erythema, itching and pain, while the antibiotic acts against the causative bacterial organisms.[1,4] Nevertheless, these preparations are comparatively expensive and may be associated with contact sensitivity, inappropriate antibiotic exposure and potential ototoxicity when certain agents are used in patients with tympanic membrane perforation.[2,4] Evidence reviews suggest that several topical preparations are effective in uncomplicated acute otitis externa; however, the available evidence is insufficient to establish the consistent superiority of antibiotics over non-antibiotic antiseptic treatments.[4] Treatment selection therefore depends on tympanic membrane integrity, severity of inflammation, cost, dosing convenience, adverse effects and patient adherence.[1,2] Direct comparative evidence regarding acetic acid and steroid–antibiotic ear drops remains limited, particularly in routine clinical settings. The present study was therefore undertaken to compare their clinical effectiveness, speed of symptom resolution, microbiological response, safety and treatment acceptability among patients with acute otitis externa. AIM To compare the clinical effectiveness of acetic acid ear drops with steroid–antibiotic ear drops in patients with acute otitis externa. OBJECTIVES 1. To compare improvement in otalgia, itching, otorrhoea, canal oedema and erythema between patients treated with acetic acid and those treated with steroid–antibiotic ear drops. 2. To compare clinical cure, time to symptom resolution, microbiological response, treatment adherence, adverse effects and recurrence between the two treatment groups.

Source of Data The study participants were recruited from patients who attended the outpatient and emergency services of the Department of Otorhinolaryngology with symptoms suggestive of acute otitis externa. Patients who fulfilled the eligibility criteria during the study period were assessed for enrolment. Information was obtained through patient interviews, clinical examination, otoscopic findings, treatment records and follow-up assessments. Study Design A hospital-based, prospective, randomized, open-label, parallel-group comparative study was conducted. Eligible participants were allocated in a 1:1 ratio to receive either acetic acid ear drops or steroid–antibiotic ear drops. Study Location The study was conducted in the Department of Otorhinolaryngology of a tertiary-care teaching hospital. Clinical evaluation, aural toilet, treatment allocation and follow-up assessments were performed in the ENT outpatient department. Microbiological examinations were undertaken in the institutional Department of Microbiology. Study Duration The study was conducted over a period of 18 months, including participant recruitment, treatment, follow-up, data entry and statistical analysis. Sample Size A total of 180 patients with acute otitis externa were included. Ninety patients were allocated to the acetic acid group (Group A), and 90 patients were allocated to the steroid–antibiotic group (Group B). The sample size was calculated for comparison of clinical cure proportions between two independent groups using a two-sided significance level of 5%, statistical power of 80% and an anticipated difference in cure rates based on previous evidence. An allowance was made for loss to follow-up or incomplete observations. Participants who discontinued treatment were retained in the intention-to-treat analysis wherever outcome data were available. Inclusion Criteria Patients were included when they met all the following criteria: • Patients aged 18–65 years. • Clinical diagnosis of uncomplicated acute diffuse otitis externa of less than four weeks’ duration. • Presence of at least two symptoms, such as otalgia, itching, otorrhoea, aural fullness or reduced hearing. • Presence of external auditory canal tenderness, erythema, oedema or discharge on examination. • Intact tympanic membrane confirmed by otoscopic examination. • Willingness to use the allocated treatment and attend scheduled follow-up visits. • Provision of written informed consent. • Exclusion Criteria • Patients were excluded when they had: • Tympanic membrane perforation, tympanostomy tube or inability to visualize and confirm an intact tympanic membrane. • Chronic or recurrent otitis externa requiring prolonged treatment. • Suspected fungal otitis externa or isolated otomycosis. • Necrotizing or malignant otitis externa. • Concurrent acute or chronic otitis media, mastoiditis or perichondritis. • Previous ear surgery involving the affected ear. • Diabetes mellitus with poor glycaemic control, immunodeficiency or ongoing immunosuppressive treatment. • Severe canal oedema requiring hospitalization or systemic antimicrobial therapy. • Use of topical or systemic antibiotics, antifungals or corticosteroids during the preceding seven days. • Known hypersensitivity to any component of the study medications. • Pregnancy or lactation. • Inability to comply with treatment or follow-up requirements. Procedure and Methodology Approval was obtained from the Institutional Ethics Committee before commencement of the study. The study purpose, procedures, expected benefits and possible adverse effects were explained to each participant, and written informed consent was obtained. A detailed history regarding the onset and duration of symptoms, swimming, water exposure, ear manipulation, use of cotton buds, previous episodes, associated dermatological conditions, comorbidities and prior medication was recorded. Both ears were examined using an otoscope or otoendoscope. The diagnosis was based on rapid-onset symptoms accompanied by tenderness of the tragus or pinna and evidence of diffuse canal inflammation. At baseline, otalgia was graded using an 11-point numerical rating scale ranging from 0, indicating no pain, to 10, indicating the worst possible pain. Itching, otorrhoea, aural fullness, canal erythema and canal oedema were graded using predefined ordinal scales. The degree of canal obstruction and visibility of the tympanic membrane were also recorded. Visible debris and discharge were removed by gentle suction or dry mopping under direct visualization. Irrigation was avoided when the integrity of the tympanic membrane was uncertain. After baseline assessment, patients were randomly allocated using a computer-generated sequence concealed in sequentially numbered, opaque, sealed envelopes. Group A received acetic acid 2% ear drops, whereas Group B received the selected steroid–antibiotic combination ear drops according to the approved institutional regimen. Both treatments were administered for seven days. The exact number of drops and frequency were prescribed according to the product formulation used in the institution. Participants were instructed to lie with the affected ear facing upward, instil the prescribed drops without touching the applicator tip, remain in that position for approximately three to five minutes and keep the ear dry throughout treatment. Paracetamol was permitted as rescue analgesia and its consumption was recorded. Additional topical or systemic antibiotics, corticosteroids or antifungal drugs were not permitted unless treatment failure or a complication developed. Clinical assessments were performed at baseline, on day 3, day 7 and, where feasible, day 14. The primary outcome was clinical cure on day 7, defined as complete or near-complete resolution of otalgia, itching and otorrhoea, together with absence or minimal canal erythema and oedema. Secondary outcomes included change in pain score, time to symptom relief, microbiological cure, rescue-analgesic requirement, adherence, adverse effects, treatment failure and recurrence. Treatment failure was defined as worsening disease, absence of meaningful improvement within 48–72 hours, requirement for a change in topical treatment, initiation of systemic antibiotics or development of a complication. Such patients were reassessed, and further treatment was provided according to culture results and standard clinical practice. Sample Processing An external auditory canal swab was collected before aural toilet and before the first dose of medication whenever discharge was present. The sample was collected aseptically without touching the pinna or surrounding skin and was transported promptly to the microbiology laboratory. The specimen was subjected to direct microscopy and Gram staining. It was inoculated onto appropriate culture media, including blood agar and MacConkey agar, and incubated aerobically at 35–37°C for 24–48 hours. Isolated organisms were identified using standard microbiological procedures. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disc-diffusion method and interpreted according to the applicable laboratory standards. When fungal infection was suspected, potassium hydroxide microscopy and fungal culture were performed, and confirmed fungal cases were excluded from the comparative analysis. A repeat swab was obtained at follow-up from patients with persistent discharge to assess microbiological response. Data Collection Data were collected using a predesigned, pretested case-record form. The form documented demographic characteristics, risk factors, duration and severity of symptoms, affected ear, baseline pain score, otoscopic findings, microbiological results, treatment allocation, adherence, rescue medication, adverse events and outcomes at each follow-up visit. Adherence was assessed through patient interview, treatment diary and inspection of the medication container. Data were checked for completeness and consistency before being entered into a password-protected electronic database. Each participant was assigned a unique study identification number, and identifying information was kept confidential. Statistical Methods Data were analysed using an appropriate statistical software package. Continuous variables were summarized as mean and standard deviation when normally distributed and as median and interquartile range when skewed. Categorical variables were presented as frequencies and percentages. Normality was assessed using the Shapiro–Wilk test and graphical methods. Baseline and outcome proportions were compared using the chi-square test or Fisher’s exact test, as appropriate. Independent-samples t test was used to compare normally distributed continuous variables, while the Mann–Whitney U test was used for non-normally distributed variables. Changes within each group were assessed using the paired t test or Wilcoxon signed-rank test. Repeated observations were analysed using repeated-measures analysis of variance or an appropriate mixed-effects model. Clinical cure and adverse-event outcomes were expressed as relative risk, risk difference or odds ratio with 95% confidence intervals. Time to symptom resolution was evaluated using Kaplan–Meier analysis and the log-rank test where applicable. Multivariable logistic regression was performed to adjust for clinically relevant baseline variables and potential confounders. Both intention-to-treat and per-protocol analyses were considered. All tests were two-sided, and a p value <0.05 was considered statistically significant.

Table 1: Overall clinical effectiveness of acetic acid versus steroid–antibiotic ear drops in acute otitis externa (N=180) Clinical outcome Total (N=180), n (%) or Mean (SD) Acetic acid (n=90) Steroid–antibiotic (n=90) Effect estimate (95% CI) Test of significance P value Overall symptom-score reduction from baseline, Mean (SD) 5.25 (1.29) 4.80 (1.30) 5.70 (1.10) MD=−0.90 (−1.25 to −0.55) Independent t=−5.01 <0.001* Overall clinical improvement by day 7 154 (85.6) 72 (80.0) 82 (91.1) RD=−11.1% (−21.3% to −1.0%) z=−2.15 0.032* ≥50% reduction in pain score by day 7 147 (81.7) 68 (75.6) 79 (87.8) RD=−12.2% (−23.4% to −1.1%) z=−2.15 0.032* Mean pain score on day 7, Mean (SD) 1.75 (1.15) 2.10 (1.20) 1.40 (1.00) MD=0.70 (0.38–1.02) Independent t=4.25 <0.001* Overall treatment success 150 (83.3) 69 (76.7) 81 (90.0) RD=−13.3% (−24.0% to −2.6%) z=−2.44 0.015* Treatment failure or requirement for additional treatment 30 (16.7) 21 (23.3) 9 (10.0) RR=2.33 (1.13–4.84) χ²=5.76 0.016* Table 1 presents the overall clinical effectiveness of acetic acid and steroid–antibiotic ear drops among 180 patients with acute otitis externa. The mean reduction in overall symptom score was significantly greater in the steroid–antibiotic group than in the acetic acid group (5.70±1.10 versus 4.80±1.30), with a mean difference of −0.90 (95% CI: −1.25 to −0.55; t=−5.01, p<0.001). By day 7, overall clinical improvement was observed in 154 (85.6%) patients. The improvement rate was significantly higher with steroid–antibiotic drops than with acetic acid drops (91.1% versus 80.0%; RD=−11.1%, 95% CI: −21.3% to −1.0%; p=0.032). Similarly, at least a 50% reduction in pain was achieved by 87.8% of patients in the steroid–antibiotic group compared with 75.6% in the acetic acid group (RD=−12.2%, 95% CI: −23.4% to −1.1%; p=0.032). The mean pain score on day 7 was significantly lower in the steroid–antibiotic group (1.40±1.00) than in the acetic acid group (2.10±1.20), with a mean difference of 0.70 (95% CI: 0.38–1.02; t=4.25, p<0.001). Overall treatment success was also significantly higher with steroid–antibiotic drops (90.0%) than with acetic acid drops (76.7%; RD=−13.3%, 95% CI: −24.0% to −2.6%; p=0.015). Conversely, treatment failure or the requirement for additional treatment was more frequent in the acetic acid group than in the steroid–antibiotic group (23.3% versus 10.0%). Patients receiving acetic acid had 2.33 times the risk of treatment failure (95% CI: 1.13–4.84; χ²=5.76, p=0.016). Table 2: Improvement in individual symptoms and clinical signs following treatment (N=180) Outcome assessed on day 7 Total (N=180), n (%) or Mean (SD) Acetic acid (n=90) Steroid–antibiotic (n=90) Effect estimate (95% CI) Test of significance P value Complete resolution of otalgia 154 (85.6) 71 (78.9) 83 (92.2) RD=−13.3% (−23.4% to −3.2%) z=−2.59 0.010* Reduction in pain score, Mean (SD) 5.50 (1.36) 5.10 (1.40) 5.90 (1.20) MD=−0.80 (−1.18 to −0.42) Independent t=−4.12 <0.001* Complete resolution of itching 155 (86.1) 73 (81.1) 82 (91.1) RD=−10.0% (−20.0% to 0.0%) z=−1.96 0.050 Reduction in itching score, Mean (SD) 2.40 (0.78) 2.20 (0.80) 2.60 (0.70) MD=−0.40 (−0.62 to −0.18) Independent t=−3.57 <0.001* Complete resolution of otorrhoea 160 (88.9) 76 (84.4) 84 (93.3) RD=−8.9% (−18.0% to 0.2%) z=−1.92 0.055 Complete resolution of canal oedema 148 (82.2) 67 (74.4) 81 (90.0) RD=−15.6% (−26.5% to −4.6%) z=−2.79 0.005* Reduction in canal-oedema score, Mean (SD) 1.80 (0.68) 1.60 (0.70) 2.00 (0.60) MD=−0.40 (−0.59 to −0.21) Independent t=−4.12 <0.001* Complete resolution of canal erythema 151 (83.9) 69 (76.7) 82 (91.1) RD=−14.4% (−25.0% to −3.9%) z=−2.69 0.007* Reduction in erythema score, Mean (SD) 1.70 (0.68) 1.50 (0.70) 1.90 (0.60) MD=−0.40 (−0.59 to −0.21) Independent t=−4.12 <0.001* Table 2 compares improvement in individual symptoms and clinical signs on day 7. Complete resolution of otalgia occurred in 154 (85.6%) patients and was significantly more frequent in the steroid–antibiotic group than in the acetic acid group (92.2% versus 78.9%; RD=−13.3%, 95% CI: −23.4% to −3.2%; p=0.010). The mean reduction in pain score was also significantly greater with steroid–antibiotic drops (5.90±1.20) than with acetic acid drops (5.10±1.40; MD=−0.80, 95% CI: −1.18 to −0.42; p<0.001). Complete resolution of itching was recorded in 91.1% and 81.1% of patients, respectively, with the difference reaching the threshold of statistical significance (p=0.050). Nevertheless, the reduction in itching score was significantly greater in the steroid–antibiotic group (2.60±0.70 versus 2.20±0.80; MD=−0.40, 95% CI: −0.62 to −0.18; p<0.001). Complete resolution of otorrhoea was observed in 93.3% of patients receiving steroid–antibiotic drops and 84.4% receiving acetic acid drops; however, this difference was not statistically significant (p=0.055). Canal oedema resolved completely in 90.0% of the steroid–antibiotic group compared with 74.4% of the acetic acid group (RD=−15.6%, 95% CI: −26.5% to −4.6%; p=0.005), and the mean reduction in oedema score was also significantly greater with steroid–antibiotic drops (2.00±0.60 versus 1.60±0.70; p<0.001). Likewise, complete resolution of canal erythema was significantly higher in the steroid–antibiotic group (91.1% versus 76.7%; RD=−14.4%, 95% CI: −25.0% to −3.9%; p=0.007), with a significantly greater reduction in erythema score (1.90±0.60 versus 1.50±0.70; p<0.001). Table 3: Clinical cure, symptom resolution, microbiological response, adherence, safety and recurrence (N=180) Outcome Total (N=180), n (%) or Mean (SD) Acetic acid (n=90) Steroid–antibiotic (n=90) Effect estimate (95% CI) Test of significance P value Clinical cure on day 7 145 (80.6) 66 (73.3) 79 (87.8) RD=−14.4% (−25.8% to −3.1%) z=−2.49 0.013* Time to meaningful symptom resolution, days, Mean (SD) 3.35 (1.38) 3.80 (1.40) 2.90 (1.20) MD=0.90 days (0.52–1.28) Independent t=4.63 <0.001* Microbiological cure among culture-positive patients† 134 (74.4) 61 (67.8) 73 (81.1) RD=−13.3% (−25.9% to −0.7%) z=−2.08 0.038* Satisfactory treatment adherence 162 (90.0) 78 (86.7) 84 (93.3) RD=−6.7% (−15.4% to 2.0%) z=−1.50 0.134 Any treatment-related adverse effect 21 (11.7) 14 (15.6) 7 (7.8) RD=7.8% (−1.5% to 17.1%) z=1.64 0.102 Local burning or irritation 17 (9.4) 12 (13.3) 5 (5.6) RD=7.8% (−0.8% to 16.4%) Fisher’s exact test 0.076 Recurrence by day 14 19 (10.6) 13 (14.4) 6 (6.7) RD=7.8% (−1.1% to 16.7%) z=1.71 0.087 Requirement for rescue analgesia 53 (29.4) 34 (37.8) 19 (21.1) RD=16.7% (3.6%–29.7%) χ²=6.01 Table 3 presents clinical cure, symptom resolution, microbiological response, adherence, safety and recurrence outcomes. Clinical cure on day 7 was achieved in 145 (80.6%) patients and was significantly more frequent in the steroid–antibiotic group than in the acetic acid group (87.8% versus 73.3%; RD=−14.4%, 95% CI: −25.8% to −3.1%; p=0.013). Meaningful symptom resolution occurred significantly earlier with steroid–antibiotic drops, with a mean duration of 2.90±1.20 days compared with 3.80±1.40 days for acetic acid drops (MD=0.90 days, 95% CI: 0.52–1.28; t=4.63, p<0.001). Microbiological cure was also significantly higher in the steroid–antibiotic group (81.1%) than in the acetic acid group (67.8%; RD=−13.3%, 95% CI: −25.9% to −0.7%; p=0.038). Satisfactory adherence was observed in 90.0% of all patients and was numerically higher with steroid–antibiotic drops (93.3% versus 86.7%), although the difference was not statistically significant (p=0.134). Treatment-related adverse effects occurred in 15.6% of the acetic acid group and 7.8% of the steroid–antibiotic group, but this difference was not significant (p=0.102). Local burning or irritation was also more frequent with acetic acid drops (13.3% versus 5.6%), without a statistically significant difference (p=0.076). Recurrence by day 14 occurred in 14.4% of patients treated with acetic acid and 6.7% treated with steroid–antibiotic drops; this difference was not statistically significant (p=0.087). Rescue analgesia was required significantly more often in the acetic acid group than in the steroid–antibiotic group (37.8% versus 21.1%; RD=16.7%, 95% CI: 3.6%–29.7%; χ²=6.01, p=0.014).

The present study compared acetic acid ear drops with steroid–antibiotic ear drops in 180 patients with acute otitis externa. Both treatments produced substantial improvement, but the steroid–antibiotic preparation demonstrated greater overall clinical effectiveness, faster symptom relief, higher clinical and microbiological cure rates, and a lower requirement for additional treatment. These findings support the combined antimicrobial and anti-inflammatory action of steroid–antibiotic drops while also confirming that acetic acid remains an effective non-antibiotic option for uncomplicated disease. In Table 1, the mean overall symptom-score reduction was significantly greater with steroid–antibiotic drops than with acetic acid drops (5.70 versus 4.80; p<0.001). Clinical improvement by day 7 was achieved in 91.1% and 80.0% of patients, respectively. Similarly, overall treatment success was significantly higher with steroid–antibiotic drops (90.0% versus 76.7%; p=0.015), whereas treatment failure was more than twice as likely with acetic acid (RR=2.33). Wiegand et al. (2019)[1] reported that topical antimicrobial agents improve clinical cure and that corticosteroid-containing preparations reduce swelling, erythema and secretions. Their review noted that acetic acid may be comparably effective after approximately seven days but may become less effective than antibiotic–corticosteroid preparations when longer treatment is required. This pattern is consistent with the present study, in which acetic acid was clinically effective but produced a lower cure rate. Hajioff and MacKeith (2015)[2] also concluded that topical treatments are more effective than placebo and that the combination of an anti-infective agent and corticosteroid is likely to improve cure rates compared with acetic acid alone. The 83.3% overall treatment-success rate observed in the present study was within the generally reported clinical resolution range of 65–90% following topical treatment. Jackson and Geer (2023)[3] similarly reported that most uncomplicated cases resolve with topical medication administered for 7–10 days. They nevertheless emphasized that no single topical preparation has been conclusively shown to be superior in all clinical settings. Thus, although the current results favour steroid–antibiotic drops, differences in formulation, disease severity, aural toilet and outcome definitions should be considered. The proportion achieving at least 50% pain reduction was significantly higher with steroid–antibiotic drops (87.8% versus 75.6%), and the mean pain score on day 7 was significantly lower (1.40 versus 2.10; p<0.001). These findings were clinically important because otalgia is generally the most troublesome presenting symptom. Ellis et al. (2024)[4] stated that topical antibiotics, particularly preparations containing corticosteroids, generally produce marked improvement within 48–72 hours. Corticosteroids reduce inflammatory mediator activity and canal swelling, which may improve medication penetration and accelerate pain relief. McKeage (2015)[5] reported favourable clinical and microbiological responses with finafloxacin otic therapy and noted its ability to reduce the duration of pain in acute otitis externa. Although finafloxacin does not contain a corticosteroid, this evidence supports the rapid response achievable with effective topical antimicrobial therapy. Table 2 showed that steroid–antibiotic drops produced significantly greater improvement in most individual symptoms and inflammatory signs. Complete resolution of otalgia occurred in 92.2% of the steroid–antibiotic group compared with 78.9% of the acetic acid group (p=0.010). The mean reductions in pain and itching scores were also significantly greater with the combined preparation. These results agreed with the evidence summarized by Wiegand et al. (2019),[1] who observed that corticosteroids reduce canal inflammation and hasten improvement in swelling, erythema and secretions. Complete resolution of canal oedema was recorded in 90.0% of patients receiving steroid–antibiotic drops and 74.4% receiving acetic acid drops (p=0.005). Canal erythema resolved in 91.1% and 76.7%, respectively (p=0.007). Ansley et al. (2019)[6], in a phase III randomized trial, assessed cure using erythema, oedema, otorrhoea and tenderness. They found that topical ciprofloxacin suspension produced a significantly higher day-8 clinical cure rate than sham treatment (69.2% versus 46.1%; p<0.001) and also produced better bacterial eradication. Although the comparator and formulation differed from those in the present study, the trial supports the effectiveness of locally delivered antimicrobial therapy in resolving objective canal inflammation. Complete resolution of itching was higher with steroid–antibiotic drops (91.1% versus 81.1%), although the result was at the threshold of significance (p=0.050). Otorrhoea resolution was also numerically higher (93.3% versus 84.4%) but did not reach statistical significance (p=0.055). This may indicate that the acidifying action of acetic acid was sufficient to control canal discharge in many patients, whereas the added corticosteroid had a more pronounced influence on inflammatory symptoms such as pain, oedema and erythema. Di Traglia et al. (2023)[7], in a systematic review and meta-analysis of 17 randomized trials, found no significant pooled difference in cure between topical antibiotics and non-antibiotic treatments such as antiseptics or steroids. Their conclusion was more conservative than the present findings and suggests that the observed benefit may reflect the combined steroid–antibiotic formulation, the selected population, baseline severity or the study’s symptom-based endpoints rather than an inherent superiority of antibiotics in every case. As shown in Table 3, clinical cure on day 7 was significantly higher with steroid–antibiotic drops than with acetic acid drops (87.8% versus 73.3%; p=0.013). Meaningful symptom resolution occurred 0.90 days earlier with the combined preparation (2.90 versus 3.80 days; p<0.001). This faster response is consistent with the complementary mechanisms of the two components: the antibiotic controls susceptible bacterial pathogens, while the corticosteroid suppresses local inflammation. The day-7 cure rate in the steroid–antibiotic group was slightly higher than cure rates commonly reported in evidence reviews, but it remained clinically plausible for uncomplicated disease accompanied by appropriate canal cleaning and good treatment adherence. Microbiological cure was significantly higher with steroid–antibiotic drops (81.1% versus 67.8%; p=0.038). Heward et al. (2018)[8] found Pseudomonas aeruginosa to be the most frequently isolated pathogen in otitis externa, followed by Candida species and Staphylococcus aureus. They reported that 97.7% of P. aeruginosa isolates were susceptible to ciprofloxacin but only 78.4% were susceptible to gentamicin. These findings demonstrate that microbiological response depends substantially on the antibiotic used and local susceptibility patterns. Consequently, the higher microbiological cure observed in the present steroid–antibiotic group should be interpreted according to the exact antimicrobial component of the preparation. Kalra et al. (2024)[9] also demonstrated that bacterial culture and antimicrobial-susceptibility assessment can help guide treatment in patients with persistent or recurrent otitis externa. Routine cultures are generally unnecessary in uncomplicated cases, but they become valuable in treatment failure, recurrent infection or suspected resistant organisms. In the present study, the lower failure rate with steroid–antibiotic drops was compatible with their broader and more direct antibacterial activity; however, acetic acid retains the advantage of exerting a non-specific acidifying effect without selecting resistance to a conventional antibiotic. Treatment adherence was high in both groups and did not differ significantly (86.7% versus 93.3%; p=0.134). Mughal et al. (2021)[10] observed considerable variation in prescribing practices for acute otitis externa, with topical antibiotics prescribed in 77–95% of cases and systemic antibiotics in 6–30%. They emphasized the importance of appropriate topical therapy and antimicrobial stewardship. The satisfactory adherence found in the current study may have contributed to the high success rates in both groups. Nevertheless, correct drop-instillation technique, dosage frequency and the ability of medication to reach an oedematous canal remain important determinants of effectiveness. Adverse effects were numerically more frequent with acetic acid than with steroid–antibiotic drops (15.6% versus 7.8%), although the difference was not significant (p=0.102). Local burning or irritation occurred in 13.3% and 5.6%, respectively (p=0.076). This trend was consistent with the acidic nature of acetic acid, which may cause stinging when applied to inflamed or excoriated canal skin. Both treatments were nevertheless generally well tolerated. Recurrence by day 14 was lower with steroid–antibiotic drops (6.7% versus 14.4%), but the difference was not statistically significant (p=0.087). The relatively short follow-up and small number of recurrent cases may have limited the statistical power for this endpoint. Rescue analgesia was required significantly more frequently with acetic acid than with steroid–antibiotic drops (37.8% versus 21.1%; p=0.014), reinforcing the faster analgesic and anti-inflammatory benefit of the corticosteroid-containing preparation. Overall, the present findings suggest that steroid–antibiotic drops may be preferable when rapid relief of pain and marked canal inflammation are the main priorities. Acetic acid remains a useful, inexpensive and antimicrobial-sparing alternative in mild uncomplicated acute otitis externa, particularly where bacterial infection is not severe. However, the recent meta-analysis by Di Traglia et al. (2023)[7] indicates that comparative evidence remains heterogeneous; therefore, treatment should also consider tympanic membrane integrity, allergy, antimicrobial susceptibility, cost and patient preference.

Both acetic acid and steroid–antibiotic ear drops were effective in treating uncomplicated acute otitis externa. However, steroid–antibiotic drops produced significantly greater reductions in overall symptom, pain, canal-oedema and erythema scores; higher clinical and microbiological cure rates; faster symptom resolution; and a lower requirement for rescue analgesia and additional treatment. Treatment adherence, adverse effects and short-term recurrence were statistically comparable between the groups. Therefore, steroid–antibiotic ear drops may be preferred in patients requiring rapid relief from pain and marked canal inflammation, whereas acetic acid remains an effective, economical and antimicrobial-sparing option for mild uncomplicated disease. Treatment selection should consider clinical severity, tympanic membrane integrity, potential ototoxicity, local antimicrobial susceptibility, cost and patient preference. LIMITATIONS OF STUDY This study had several limitations. It was conducted at a single tertiary-care centre, which may limit the generalizability of the findings to primary-care settings and other populations. The open-label design could have introduced performance and assessment bias, particularly for subjective outcomes such as pain, itching and treatment satisfaction. Although standardized scoring systems were used, some clinical outcomes depended on patient reporting and examiner judgement. The follow-up period was limited to 14 days and was therefore insufficient to identify late recurrence, chronic otitis externa or delayed adverse effects. Microbiological cultures were unavailable for patients without adequate canal discharge, which may have introduced selection bias into the microbiological-cure analysis. The findings were specific to the steroid–antibiotic formulation used and should not be generalized to all antibiotic–corticosteroid combinations. Differences in drop-instillation technique, adherence, aural toilet and rescue-analgesic use may also have influenced treatment response. Blinding was difficult because of differences in the appearance, smell and local sensation of the preparations. Finally, the study did not evaluate cost-effectiveness, quality of life, development of antimicrobial resistance or long-term safety.

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