Epidemiology of Nasal Polyps

Mounting evidence suggests that nasal polyposis (NP) is a clinical manifestation of multiple possibly coexisting immunologic pathways, and because this entity likely reflects an array of disease states, the epidemiology is difficult to characterize. Phenotypically, chronic rhinosinusitis (CRS) can be classified as either CRS without NP or CRS with NP. CRS without NP, in general, reflects TH1-mediated inflammation [45]. Idiopathic CRSwNP comprises the vast majority of cases of NP, and this term typically implies a clinical picture of diffuse sinonasal polyposis dominated by TH2-mediated (eosinophilic) responses, at least in western patients. In rare cases, a distinct genetic, immunologic, or metabolic defect has been associated with the development of diffuse NP, and these cases will be discussed below. Furthermore, CRS with NP must be differentiated from antrochoanal polyps, which account for only 5% of polyp cases [24]. Antrochoanal polyps are usually unilateral and solitary and most often arise from the maxillary sinus. This is a distinct disease process that often presents at a younger age compared to CRSwNP. In contrast to CRSwNP, antrochoanal polyps reveal lesser degrees Allergic fungal rhinosinusitis is a known underly › ing pathophysiologic etiology in a subset of CRS patients and is strongly associated with NP. Ethnic and geographic variation has emerged as › a potential modifier in NP pathophysiology. Core Messages