Classification	Duration	History, examination	Special notes
Acute	Up to four weeks	The presence of two or more Major signs and symptoms; one Major and two or more Minor signs or symptoms; or nasal purulence on examination*	Fever or facial pain/pressure does not constitute a suggestive history in the absence of other nasal signs and symptoms. Consider acute bacterial rhinosinusitis if symptoms worsen after five days, if symptoms persist for 10 days or with symptoms out of proportion to those typically associated with viral infection.
Subacute	Four to < 12 weeks	Same	Complete resolution after effective medical therapy.
Recurrent acute	Four or more episodes per year with each episode of at least seven days' duration; absence of intervening signs and symptoms	Same	—
Chronic	12 weeks or more	Same	Facial pain/pressure does not constitute a suggestive history in the absence of other nasal signs and symptoms.