xRead - September 2022

Wise et al.

Page 157

ear space. The frequently observed clinical association of Eustachian tube symptoms and AR is corroborated by high-level evidence that demonstrates that in AR patients, nasal challenge with histamine or relevant aeroallergens results in transient Eustachian tube obstruction. 1948-1950 These studies used the 9-step inflation-deflation swallow test of Eustachian tube function developed by Bluestone and Cantekin. 1951 The development of negative middle ear pressure after allergen challenge corresponds with increases in nasal airway resistance. 1952 AR appears to increase the incidence of Eustachian tube dysfunction relative to control populations, 1953 and natural pollen exposure has been associated with negative middle ear pressures 1954 and defects in Eustachian tube opening. 1955 This body of evidence supports a direct causal role for AR in some cases of Eustachian tube dysfunction (Table X.G-1). • Aggregate Grade of Evidence: C (Level 1b: 3 studies; Level 2b: 1 study; Level 3b: 1 study; Level 4: 2 studies; Table X.G-1). Otitis media— The role of allergy as a causative factor in otitis media has not been clearly demonstrated. Historically, allergy was considered an important etiologic factor in otitis media. However, as clinical definitions have become more stringent and evidence expectations have evolved, it has become apparent that a clear etiopathogenic connection between AR and otitis media is yet to be demonstrated. Investigations into the connection between these 2 conditions have examined the evidence for type 1 IgE-mediated inflammation in the middle ear space, epidemiologic associations between the 2 conditions, and the effect of allergy treatment on otitis outcomes. The middle ear mucosa may behave in a manner similar to nasal mucosa and be a site of local IgE-mediated inflammatory reactions. 1956-1958 However, direct intranasal allergen challenge in allergic subjects does not appear to cause otitis media. 1948-1950 Studies of the epidemiologic association of AR or atopy and otitis media with effusion (OME) are widely discordant. Some studies have found no significant difference in allergic sensitization or clinical allergy in OME patients compared to control groups, 1959,1960 while others have shown a dramatically increased prevalence of IgE sensitization or clinical allergy in OME patients, 1961-1964 or that AR is an independent risk factor for the development of OME. 1965 Finally, some studies suggest a nearly universal association of OME and allergic disease. 1966-1970 These inconsistencies in the literature are likely related to highly selected patient populations in specialty practices, variability in allergy test methods, and the problems incumbent in identifying appropriate control groups. Thus, the relationship of allergy and OME remains unclear (Table X.G-2). In general, randomized placebo-controlled trials have shown that INCS do not improve OME outcomes. 1971-1973 Also, a Cochrane systematic review found no benefit of antihistamines and/or decongestants in the treatment of OME. Thus, traditional medical treatments for AR do not appear to be an effective option for OME and recent otitis media CPGs recommend against the use of these agents. 1974 Additional investigation is needed to discern the effect of allergy on the incidence or natural history of OME and to determine if AIT has beneficial effects. • Aggregate Grade of Evidence: C (Level 2b: 2 studies; Level 3b: 3 studies; Level 4: 11 studies; Table X.G-2).

Author Manuscript Author Manuscript Author Manuscript Author Manuscript

Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.