Role of Allergy in Eustachian Tube Dysfunction.

Abstract

Eustachian tube dysfunction (ETD) presents with symptoms of aural fullness and pressure, muffled hearing, tinnitus, and otalgia. When severe, it can lead to many common ear disorders such as otitis media with effusion, tympanic membrane retraction/perforation, and cholesteatoma. These diseases are prevalent in both the pediatric and adult population and significantly impact quality of life. The pathophysiology of ETD in the absence of an obstructive lesion has long been debated but is thought to be related to functional obstruction (i.e., inefficient tensor veli palatini muscle) and/or nasal cavity and nasopharyngeal inflammation. In the acute setting, the most common cause of nasal inflammation is an upper respiratory infection. When symptoms become chronic, however, the inflammation is thought to be associated with nasal irritants such as nasal allergens, i.e., allergic rhinitis (AR). The purpose of this review is to summarize our current understanding of the relationship between allergy and ETD. Past studies are either lacking or have reported equivocal findings regarding the relationship between allergy and ETD, and the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis has deemed the current level of evidence linking AR and ETD as low quality. A more recent study using a large adult population dataset did support an association between AR and ETD, but did not find that all cases of ETD are related to allergies. Furthermore, current evidence suggests that the use of medications that can decrease intranasal inflammation, such as intranasal corticosteroids or oral antihistamines, does not result in significant symptomatic improvement in patients with ETD. However, these studies included all patients with ETD, and evidence is lacking regarding the treatment effect of these medications on the subset of patients with concurrent AR and ETD. Current best evidence does support an association between AR and ETD; however, not all patients with ETD suffer from AR, and vice versa. Further research is necessary to understand the mechanism behind this positive association and to elucidate the cause of chronic ETD in patients without associated allergies.