- Meeting criteria for a diagnosis of chronic rhinosinusitis (CRS) using self-reported symptoms and based on clinical guidelines; eligible subjects will report: • sinonasal symptoms for at least 12 weeks; • a constellation of sinonasal symptoms including either two or more major factors, or 1 major and 2 minor factors (see Table 1 below), or chronic nasal purulence for 12 or more weeks; and • a moderate to severe HRQoL impact (≥ 3 points on a 0-10 Likert severity scale) as assessed by a single item question:11 "What has been the average level of your sinus symptoms daily over the past month on a 0-10 scale?" This item is consistent with eligibility criteria used in prior NI studies.