Clinical recommendation	Evidence rating	References
The diagnosis of chronic rhinosinusitis is based on the presence of at least two out of four cardinal symptoms for at least 12 weeks, in addition to objective evidence on physical examination or radiography.	C	18
Non–contrast-enhanced computed tomography is the imaging study of choice to confirm the diagnosis of chronic rhinosinusitis.	C	19, 20
Nasal saline irrigations improve sinonasal symptoms in patients with chronic rhinosinusitis.	A	25–27
Intranasal corticosteroid sprays improve sinonasal symptoms in patients with chronic rhinosinusitis.	A	33, 35, 36
Short courses (up to three weeks) of oral corticosteroids, alone or as an adjunct to standard maintenance therapy, improve sinonasal symptoms in the short term in patients with chronic rhinosinusitis and polyps.	A	45, 46
Oral antibiotics, given for up to three weeks, may be considered as a treatment option for acute exacerbations of chronic rhinosinusitis.	C	31, 32