While these studies have provided evidence to support the contention that nasal allergy contributes to OME, they have not confirmed the hypothesis in its entirety. The provocative intranasal antigen or histamine challenges have induced eustachian tube obstruction but have not resulted in OME. Because we wanted to minimize the possible risk of creating middle ear pathology following a provocative intranasal challenge, the absence of a resultant OME was anticipated for two reasons: the relatively brief duration of eustachian tube obstruction after challenge and the use of adult study subjects. Following intranasal provocative challenge, the developed tubal obstruction persisted only for several hours to a few days. In monkeys OME does not develop until 1 to 4 weeks after creating a surgical functional eustachian tube obstruction. Thus, eustachian tube obstruction must be sustained for a week or more for OME to develop. Further, a number of studies have suggested that eustachian tube function improves with age and has been related to the fact that OME is more prevalent in younger children. If the younger child has some degree of functional eustachian tube obstruction, then the development of an antigen provoked, histamine mediated eustachian tube obstruction might be expected to have more severe and prolonged effects at a lesser antigen dosage. It is our hypothesis that allergy and other pathophysiologic events that release or generate mediators of inflammation in the nasopharynx play a role in the pathogenesis of middle ear diseases.(ABSTRACT TRUNCATED AT 250 WORDS)