Type	Definition
Acute rhinosinusitis	Up to four weeks of purulent nasal drainage (anterior, posterior, or both) accompanied by nasal obstruction; facial pain, pressure, or fullness; or both
		Purulent nasal discharge is cloudy or colored (opposed to clear secretions that typically accompany viral upper respiratory infection) and may be reported by the patient or seen during physical examination
		Nasal obstruction may be reported by the patient as nasal obstruction, congestion, blockage, or stuffiness, or it may be diagnosed on physical examination
		Facial pain, pressure, or fullness may involve the anterior face or periorbital region or may manifest with localized or diffuse headache
Viral rhinosinusitis	Acute rhinosinusitis that is presumed to be caused by viral infection; physicians should diagnose viral rhinosinusitis when symptoms or signs of acute rhinosinusitis are present for less than 10 days and symptoms are not worsening
Acute bacterial rhinosinusitis	Acute rhinosinusitis that is presumed to be caused by bacterial infection; physicians should diagnose acute bacterial rhinosinusitis when:
		Symptoms or signs of acute rhinosinusitis are present 10 days or more after onset of upper respiratory symptoms
			or
		Symptoms or signs of acute rhinosinusitis worsen within 10 days of initial improvement (i.e., double worsening)
Chronic rhinosinusitis	Two or more of the following signs and symptoms lasting 12 weeks or more:
		Mucopurulent drainage (anterior, posterior, or both)
		Nasal obstruction (congestion)
		Facial pain, pressure, or fullness
		Decreased sense of smell
			and
	Inflammation documented by one or more of the following findings:
		Purulent mucus or edema in the middle meatus or ethmoid region
		Polyps in the nasal cavity or middle meatus
		Radiographic imaging shows inflammation of the paranasal sinuses
Recurrent acute rhinosinusitis	Four or more episodes per year of acute bacterial rhinosinusitis without signs or symptoms of rhinosinusitis between episodes
	Each episode should meet the diagnostic criteria for acute bacterial rhinosinusitis