A double-blind randomised clinical trial of the treatment of otitis externa using topical steroid alone versus topical steroid-antibiotic therapy.

The objective of the study was to determine if the addition of topical antibiotic increases the efficacy of topical steroid in controlling otitis externa. A double-blind randomised controlled trial was performed from February 2003 to April 2005 in an otolaryngology emergency clinic (acute urban teaching hospital) in the United Kingdom. Patients were followed up for 2 weeks. Forty-five adults with otitis externa based on the presence of oedema, discharge or debris in the outer ear canal were recruited. The patients were randomised to one of the two treatment groups, namely using betamethasone sodium phosphate 0.1% (Vista-Methasone) or betamethasone sodium phosphate 0.1% with neomycin sulphate 0.5% (Vista-Methasone N), and were instructed to use the trial medication at three drops three times a day for 2 weeks. Subjects' visual analogue symptom scores (blockage, pain, discharge, and itching) for otitis externa pre-treatment (day 0) and post-treatment (day 15), percentage changes in visual analogue symptom scores as a result of treatment, proportion of patients whose symptom scores failed to improve or deteriorated on treatment were analysed. The two experimental arms demonstrated statistically similar presenting symptom scores at recruitment (mean symptom scores of 19.2 for betamethasone group and 28.7 for betamethasone-neomycin group). The mean symptom score change in response to treatment was 82.8 and 47.8% in the betamethasone-neomycin and betamethasone-alone groups, respectively. There was no statistically significant difference between the groups in median percentage symptom score change in response to treatment. All patients in the betamethasone-neomycin group showed symptom improvement but in the betamethasone alone group, five patients got worse (Fishers exact, P = 0.05). Topical antibiotic-steroid combination therapy is superior to steroid-alone treatment for symptomatic control of otitis externa.