To review the current knowledge surrounding different chronic rhinosinusitis (CRS) presentations and the relative roles of nasal polyps, eosinophilia, and allergies in discerning phenotypes.PubMed literature review.Articles discussing the various phenotypes of CRS with emphasis on pathologic and immune mechanistic studies that distinguish disease.Current guidelines primarily separate CRS based on the presence or absence of nasal polyps. This is largely driven by the tendency of eosinophilic disease to present with nasal polyps (NPs) in contrast to noneosinophilic presentations, which less often lead to the development NPs. Further separations have been proposed based on expression of aeroallergen sensitization.The presence of NPs may only poorly predict the presence of an underlying eosinophilic process and as such may have poor utility in forming the basis for recommending eosinophil-target therapies. Similarly, there is little evidence to support a significant role for aeroallergen exposure in contributing to the presence, severity, or natural history of CRS. Appropriate separation of CRS into specific phenotypes will allow therapeutic approaches to be individualized to each distinct presentation.