Categorization of eosinophilic chronic rhinosinusitis

Abstract

The presence of eosinophilia histopathologically in sinusitis is frequently associated with greater disease objectively and a decreased likelihood of surgical success. Eosinophilic chronic rhinosinusitis encompasses a wide variety of etiologies and associations that can be grouped under this umbrella term. In addition, this term can be further divided into those patients with no polyps and those with polyps. The purpose of this review is to detail the epidemiology of eosinophilic chronic rhinosinusitis, to define known and potential subcategories, and to discuss targeted therapeutic interventions. Eosinophilia is frequently, but not exclusively, caused by IgE-mediated hypersensitivity and is dominated by the associated cytokine milieu of Th2 inflammation. Thus, allergic rhinitis or allergy is a subcategory and not synonymous with eosinophilic chronic rhinosinusitis. Recent findings supporting mechanisms that promote eosinophilic infiltration are discussed and include the following subcategories: super antigen-induced eosinophilic chronic rhinosinusitis, allergic fungal sinusitis, nonallergic fungal eosinophilic chronic rhinosinusitis, and aspirin-exacerbated eosinophilic chronic rhinosinusitis. Undoubtedly there are other mechanisms and categorizations of eosinophilic chronic rhinosinusitis as yet unknown. It is possible, and in fact probable, that some patients may have overlapping mechanisms for eosinophilia. Corticosteroid therapy is an important treatment across all eosinophilic disorders and a profoundly potent but nonspecific antiinflammatory agent. Within each subcategory a specific antibacterial, antifungal, or immune modulation may be indicated. The subcategories of eosinophilic chronic rhinosinusitis are discussed in light of recent findings and treatment recommendations.