Eosinophils from Physiology to Disease: A Comprehensive Review

Figure 4

Prevalence of selected upper airways diseases according to the clinical phenotype. Several inflammatory diseases of the mucosal layer of the nose and paranasal sinuses may involve eosinophil-related pathogenic events. Taken singularly and together, these entities have a high prevalence in the general population and show multiple overlapping clinical as well as possibly pathophysiological overlaps. In particular chronic rhinosinusitis is very frequent in the general population and associates in a large number of cases with the development of hyperplasia (i.e., nasal polyposis, NP), which in turn is a frequent comorbidity in patients with asthma. Paradoxically to some extent, the prevalence of nasal polyposis in allergic rhinitis (AR) is lower than expected, although atopic patients probably have a worse clinical phenotype. By contrast, nasal polyposis is frequent in patients with nonsteroidal anti-inflammatory drugs (NSAIDs), non-IgE-mediated hypersensitivity, a possible cause of nonallergic rhinitis. However, at least part of the clinical spectrum of nonallergic rhinitis may be characterised by the presence of local IgE responses (LAR). The epistemological borders of this clinical entity are still a matter of debate.