ObjectivesAtelectatic eardrum and adhesive otitis media in children are related to persistent otitis media with effusion (OME) and eustachian tube dysfunction in infancy. However, the pathogenesis of these diseases is not fully understood, and some cases even progress to pars tensa cholesteatoma. This study analyzed the clinical characteristics of children with atelectatic eardrum and adhesive otitis media to clarify associated causes of and risk factors for progression of these middle ear pathologies in children. Patients and methodsThis retroactive study included 38 ears of 31 children with atelectatic eardrums (atelectasis group), and 19 ears of 17 children with adhesive otitis media (adhesive OM group). Thirty-two contralateral non-cholesteatoma ears of 32 children with congenital cholesteatoma were also examined as a control group. Participants were aged 15 or younger. Life history (obtained via questionnaire), associated diseases, hearing acuity, aeration and development of the temporal bone were investigated. ResultsAll children in the atelectasis and adhesive OM groups had a history of recurrent acute otitis media (rAOM) and/or OME. The prevalence of perennial allergic rhinitis was 18 cases (58%) in the atelectasis group and 16 cases (94%) in the adhesive OM group. The prevalence of perennial allergic rhinitis was significantly higher in the adhesive OM group compared to the control group (P < 0.01). The development of mastoid air cells, categorized by MC classification, showed MC0 + MC1 (poor pneumatization) in 19 ears (50.0%) with atelectatic eardrums and 12 ears (63.2%) with adhesive OM. Poor pneumatized mastoid was more frequently observed in the ears of the atelectasis and adhesive OM groups compared to the control group (P < 0.01). No significant difference was found in regards to aeration of the middle ear between the two groups; however, aeration was significantly poorer in both groups compared to the control group (P < 0.01). Three characteristics were analyzed using multivariate logistic regression: perennial allergic rhinitis (odds ratio [OR] 4.319, P = 0.013), poor mastoid pneumatization (OR 8.457, P = 0.012), and pars flaccida retraction pocket (OR 20.897, P = 0.006). These characteristics were shown to be significant risk factors for atelectatic eardrums and adhesive OM. In addition, the predisposition to perennial allergic rhinitis was shown to be the most important factor in the progression from atelectatic eardrum to adhesive otitis media (OR 16.615, P = 0.012). ConclusionChildren with perennial allergic rhinitis, poor development of mastoid air cells, poor aeration of the temporal bone, and with pars flaccida retraction pocket were at an increased risk of developing an atelectatic eardrum and adhesive OM. In particular, perennial allergic rhinitis was shown to be a significant risk factor in the progression from atelectatic eardrum to adhesive otitis media. Allergic inflammation may affect not only the nasal passages but also the eustachian tube, resulting in persistent middle ear dysfunction. Therefore, children with rAOM/OME who have these risk factors should be carefully monitored and treat over time in effort to prevent progression of pathology.