Immunologic-mediated eustachian tube obstruction: a double-blind crossover study

Eight subjects with seasonal allergic rhinitis confirmed by positive skin tests and serum radioallergosorbent test to ragweed or timothy grass pollen were identified. A double-blind provocative antigen challenge was performed with intranasal insufflation of 50 mg of dry pollen to which the subject was either sensitive (ragweed or timothy) or not sensitive (pine). Before and after pollen insufflation, measurements of nasal function by nasal rhinomanometry and eustachian tube (ET) function by the nine-step tympanometry test were performed for up to 14 days. The ability to dilate the ET was documented in 14 of the 16 ears of the eight subjects before challenge. Within 30 min after antigen challenge transient obstruction of the ET associated with inability to dilate upon swallowing was observed in all 14 ears. Clinical symptoms of allergic rhinitis, including rhinorrhea and nasal obstruction, were produced in all subjects. ET function changes were reversible in three of 14 ears within 2 hr but persisted for more than 3 days in six of the ears. As a control, insufflation of pine pollen did not alter ET function or rhinomanometric values or produce clinical symptoms in the eight subjects. These findings suggest an allergic basis for ET obstruction and possibly for the development of otitis media with effusion.