Is biofilm the cause of chronic otitis externa?

Objectives/hypothesis: This study was undertaken in two phases. In the first phase, we considered patients affected by chronic external otitis treated either by chemical ear peeling (CEP) or by antibiotic/steroid treatment to compare the clinical and microbiological outcomes. In the second phase, we compared the microscopic findings observed in the CEP samples of patients affected by chronic otitis externa's acute exacerbation or by acute otitis externa to demonstrate the role of biofilm in the pathogenesis of chronic otitis externa.

Study Design: Prospective, double-blind, controlled study.

Methods: In phase 1 we compared clinical and microbiological data collected from two groups of 25 patients with chronic otitis externa treated by CEP or by conventional antibiotic/steroid treatment. In phase 2 we compared the results of the optical and electron microscopic analysis of specimens obtained by performing CEP in two groups of patients (25 with chronic otitis externa exacerbation and 15 with acute otitis externa).

Results: In phase 1 the disease control rate yielded markedly better results when treated with CEP. In phase 2 biofilms were identified in 23 of the 25 patients with chronic otitis externa exacerbation (92%) and in only three acute external otitis cases (20%).

Conclusions: CEP is a simple and effective method for the treatment of chronic external otitis. The removal of the bacterial biofilm has a high correlation with a long-term clinical remission.