Chronic rhinosinusitis (CRS) is a complex disease consisting of several disease variants
with different underlying pathophysiologies. Limited knowledge of the mechanisms of these
disease subgroups is possibly the greatest obstacle in understanding the causes of CRS
and improving treatment. It is generally agreed that there are clinically relevant CRS
phenotypes defined by an observable characteristic or trait, such as the presence or
absence of nasal polyps. Defining the phenotype of the patient is useful in making …