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Evidence summaries

Topical Antimicrobial Treatment for Otitis Externa

Topical antimicrobial treatments appear to be effective for acute otitis externa but there is little evidence of difference between different antimicrobial agents. Level of evidence: "B"

A systematic review 1 including 20 RCTs with a total of 3 289 subjects was abstracted in DARE. Antimicrobials (neomycin/methylprednisolone and acetic acid/glyceryl triacetate) were associated with a significant increase in clinical cure rate at 3 to 10 days compared with placebo (RD 0.46, 95% CI 0.29 to 0.63; 2 RCTs, n=89) and bacteriological cure rate (RD 0.61, 95% CI 0.46 to 0.76; 2 RCTs, n=112). Compared with steroid alone (betamethasone and hydrocortisone butyrate), steroid-antibiotic combinations (oxytetracycline/polymyxin B/hydrocortisone) were associated with a significant decrease in clinical cure rate at 7 to 11 days (RD -0.20, 95% CI -0.38 to -0.03; 2 RCTs, n=92). Quinolone antibiotics (ofloxacin, ciprofloxacin with and without dexamethasone or hydrocortisone) were associated with a significant increase in bacteriological cure rate compared with nonquinolone antibiotics (gentamicin, tobramycin, polymyxin/hydrocortisone plus neomycin and oxytetracycline; RD 0.08, 95% CI 0.006 to 0.16; 6 RCTs, n=980; significant heterogeneity, I2 74%). The difference between treatments was no longer significant after the exclusion of one small study with an RD at least twice that of the other studies, but heterogeneity remained significant (p=0.021). There were no significant differences in clinical cure rates and adverse events between quinolone antibiotics and nonquinolone antibiotics, based on analyses of between 476 and 1475 patients from between 2 and 6 studies. Significant heterogeneity was found in most of these analyses. There were no significant differences between antiseptic versus antimicrobial treatments and steroid-antimicrobial combinations versus antimicrobial alone.

Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies, heterogeneity in interventions and outcomes).

References

Primary/Secondary Keywords