Clin. Otolaryngol. 1991, 16, 547-548

A randomized prospective comparison of two methods of administering topical treatment in otitis externa G.D.BARR & M.AL-KHABORI From the Department of Otolaryngology, Stobhill General Hospital, Glasgow, UK Accepted for publication 30 October 1990


(1991) Clin. Otolaryngol. 16, 541-548

A randomized prospective comparison of two methods of administering topical treatment in otitis externa Ten patients with bilateral moderate or severe otitis externa were studied. Following aural toilet each patient was subjected to two different treatments: one ear had alternate day dressings containing a topical antibiotic/steroid mixture, while the external canal of the other was filled with the same topical preparation (sump filling). Improvement in the severity of the otitis externa was assessed after 1 week. 9 out of 10 ear canals improved in each group. An estimate of the relative cost of each treatment was made and sump filling was found to be less expensive. The results suggest that sump filling is a low cost alternative to standard treatment in moderate and severe otitis externa. Keywords topical antibiotics aural toilet ear dressings

Treatment of the more severe forms of otitis externa involves aural toilet, followed by the application of a topical preparation, commonly on a ribbon gauze wick. This study compares an alternative method of applying a topical preparation with the use of the same topical preparation and standard ear dressing in moderate and severe otitis externa.

Patients and method Ten patients with either moderate or severe bilateral otitis externa were studied. None of the patients had received any recent treatment for the otitis externa. The seventy of the otitis externa was assessed objectively by an independent examiner during microscopic aural toilet using a scale of 1 to 5 (Table 1). Swabs were taken from each ear for bacteriological study. Each patient received two different treatments, one to each ear. The allocation of the treatments to the ears was randomized according to date of birth. The two treatments were (i) ear dressing: an antibiotic steroid mixture applied on 1.25-cm width ribbon gauze; the dressing was changed on alternate days; (ii) sump filling: the same antibiotic steroid mixture was applied using a 2-ml plastic syringe fitted with a Correspondence: G.D.Barr, ENT Department, Stobhill General Hospital, Glasgow G21 3UW, UK.

Zoellner suction end (the suction end was the same as that used for aural toilet after flushing it clean). Starting from the tympanic membrane the ear canal was filled laterally. The ear was then left alone for 1 week. The topical preparation used was of equal parts of oxytetracycline 3% ointment and fluocinolone 0.025% cream (which are miscible, giving a more viscid consistency than a cream alone). In 3 patients with chronic recurrent otitis externa, gentamicin 0.3% cream, nystatin ointment 100000 units/g and fluocinolone 0.025% cream were used in equal parts. In all patients the mixture used was the same for both ears. The patients were reviewed after 1 week and the severity of the otitis externa reassessed by the same independent examiner. Table 1. Seventy scale for otitis externa

Discharge 0 = none I = coating of moist discharge 2 = discharge filling the lumen Swelling 0 = none 1 = meatal wall swollen; whole tympanic membrane visible 2 = meatal wall swollen; up to f tympanic membrane obscured Erythema 0 = none 1 = present



G.D.Barr and M.Al-Khabori

Table 2. Cost of treatments-relative -~






1.25 cm ribbon gauze €00.085 x 3 same

2 ml syringe EOO.0 16 same

Initial labour cost and suction end Topical preparation €00.24 €02.885 Subsequent labour cost* €03.38 Cost per treatment

€00.08 nil €00.096

*Grade F nurse rate E05.77Jh. Severity

Figure 1. Severity of otitis externa before and after treatment. a, Dressing before; b, dressing after. c. Sump-filling before; d, sumpfilling after.

Results Considering an improvement of 2 in the severity scale to be significant, 9 out of 10 improved in each group (Figure I). The confidence intervals for the difference in the proportions improving were calculated by the exact method, using a statistics computer program.' The 95% confidence interval for the difference between the proportions improving in each group was found to be 0-20%, which is a small difference. Despite the wide variety of pathogens isolated (similar to other studies involving otitis externa2), 5 patients had the same pathogen isolated in both ears, and only 1 patient had a different isolate between the ears. This similarity in pathogens in bilateral otitis externa suggests that the aetiology is often the same for each ear. With an equally good response in otitis externa using either ear dressings or sump-filling, an estimate of the relative cost of each treatment was made (Table 2).

Compared to ear dressings, sump-filling is cheaper and should therefore be considered as the initial treatment in patients where the above criterion is met. The cost of the topical preparation used in sump-filling is minimal because 60 g of the antibiotic/steroid mixture is sufficient for at least 40 treatments. Although aluminium acetate3 has been advocated as a low-cost treatment for otitis externa, the cost of sump-filling would be less than that of ear dressings containing aluminium acetate. In this series, 3 out of 10 ears resolved completely after 1 week with sump-filling. The 6 that improved but resolved incompletely had treatment continued with ear drops for a further week. We prefer the use of a low-cost steroid preparation (betamethasone 0.1 % ear drops with or without neomycin 0.5%), to enhance the resolution of any residual inflammation similar to the use of gentamicin and hydrocortisone in CSOM.? If no improvement occurs after 1 week, the bacteriology is reviewed and ear dressings are used after aural toilet. This technique may be useful in elderly or disabled patients who find difficulty in applying ear drops and also in those likely to comply poorly with self-administered treatment. Generally, patients find it inconvenient to attend for ear dressings and therefore sump-filling is a preferable alternative.

Discussion Aural toilet followed by ear dressing is traditionally considered to be an effective method of treatment in the more severe forms of otitis externa. In this study a significant improvement occurred after 1 week in both treatment groups. The confidence limits show that in a larger series, no difference greater than 20% in the numbers improving would be expected between the 2 treatment groups. As a significant number improved in each treatment group, the sump-filling technique can be regarded as effective, providing there is enough space in the ear canal to act as a sump (1.e. half the tympanic membrane can be seen).

References 1 GARDNER M.J., GARDNER S.B. & WINTERP.D. (1989) Confidence interval analysis. Microcomputer program. British Medical Journal Publications, London. 2 SLACKR.W.T. (1987) A study of three preparations in the treatment of otitis externa. J . Laryngol. Otol. 101, 533-535 3 CLAYTON M.I., OSBORNE J.E., RUTHERFORD D. & RIVRONR.P. (1990) A double-blind, randomised, prospective trial of a topical antiseptic versus a topical antibiotic in the treatment of otorrhoea. Clin.Otolaryngol. 15, 7-10 4 PICOZZIG.L., BROWNING G.G. & CALDER I.T. (1983) Controlled trial of gentamicin and hydrocortisone ear drops in the treatment of active chronic otitis media. Clin. Otolaryngol. 18, 367-368

A randomized prospective comparison of two methods of administering topical treatment in otitis externa.

Ten patients with bilateral moderate or severe otitis externa were studied. Following aural toilet each patient was subjected to two different treatme...
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