Prospective randomised single‐blind controlled trial of glacial acetic acid versus glacial acetic acid, neomycin sulphate and dexamethasone spray in otitis externa and infected mastoid cavities

Abstract

The literature reports the merits of antibacterial, antibiotic and steroid agents in treating otological infections but no controlled clinical trial has directly compared 2% glacial acetic acid (EarCalm; Stafford-Miller Ltd, Brentford, UK) against 2% glacial acetic acid, 0.1% dexamethasone and 3250 U/ml of neomycin sulphate (Otomize; Stafford-Miller Ltd) in the treatment of otitis externa and infected mastoid cavities. Prospective, single-blind randomised controlled trial. Outpatients, Derby Royal Infirmary, Derby, UK. Emergency and GP referrals with acute otitis externa (n = 53) and infected mastoid cavities (n = 56). Otoscopy was performed at initial randomisation and then at 2 and 4 weeks, the ear assessed for active and inactive disease. Patients with active otitis externa, 71% (15/21) resolved with glacial acetic acid, dexamethasone and of neomycin sulphate after 2 weeks, increasing to 86% (18/21) after 4 weeks treatment. Patients on glacial acetic acid had only 38% (12/32) resolution after 4 weeks (P < 0.0005). Two per cent glacial acetic acid, dexamethasone and neomycin sulphate resolved only 30% (8/27) of infected mastoid cavities compared to only 10% (3/29) on glacial acetic acid (P < 0.07). A further 2 weeks treatment this increased to 67%, (18/27) with glacial acetic acid, dexamethasone and neomycin sulphate and 48% (14/29) with glacial acetic acid. These results are not statistically significant. Glacial acetic acid, dexamethasone and neomycin sulphate is significantly more effective in treating otitis externa when compared with glacial acetic acid. This effect failed to be significant in the infected mastoid cavities group. We therefore recommend that in conjunction with aural toilet, antibiotic/steroid combination is more effective than an antibacterial agent for otitis externa. Larger numbers of infected mastoid cavities are required to be studied.