Clinical characteristics of so called eosinophilic otitis media

Although "eosinophilic otitis media" is not as uncommon a condition as was previously believed, its cause and pathogenesis are not yet fully understood. The purpose of this study was to describe the clinical characteristics in patients with "eosinophilic otitis media" to clarify its pathogenesis.

Seven adult patients with persistent and intractable otitis media with viscous middle ear effusion containing many eosinophils, who were also under treatment for bronchial asthma, were studied. The following examinations were conducted: nasopharyngeal endoscopy, pure-tone audiometry, eustachian tube function test, temporal bone CT scan, blood analysis, bacterial and fungal culture of middle ear effusion, histological study of the middle ear and nasal specimens, and measurement of eosinophilic cationic protein (ECP) in middle ear effusion.

Some patients had persistent perforation with papillomatous granulation tissue arising from the mesotympanic mucosa, and all the patients had nasal polyposis. The pure-tone audiometry showed the mixed-type of hearing loss in all the patients, and the hearing level deteriorated progressively during the course in some patients. The eustachian tube function was not always poor but was patulous in some cases. The most severely diseased areas were in the eustachian tube and mesotympanum by temporal bone CT images. All the seven patients had the high levels of total serum IgE, but the RAST scores were negative in three patients and low grade in three patients. The accumulation of eosinophils was observed in middle ear effusion, middle ear mucosa and nasal polyps, and the eosinophils were highly activated with degranulation. High level of ECP was also recovered from middle ear effusion.

Active eosinophilic inflammation occurs in the entire respiratory tract, including the middle ear in these patients. From our present investigation, we propose the criteria and clinical characteristics of "eosinophilic otitis media".