Yes, Sinusitis is Inflammation or Infection of the Sinuses
Yes, sinusitis is defined as inflammation of one or more of the paranasal sinuses, with infection being the most common cause. 1 The term "rhinosinusitis" has been suggested as more accurate since rhinitis typically precedes sinusitis, sinusitis without rhinitis is rare, and the mucosa of the nose and sinuses are contiguous. 1
Definition and Classification
Sinusitis represents inflammation of the paranasal sinuses, classified primarily by duration of symptoms: 1
Acute sinusitis: Symptoms lasting less than 4 weeks, consisting of persistent upper respiratory tract infection symptoms, purulent rhinorrhea, postnasal drainage, anosmia, nasal congestion, facial pain, headache, fever, and cough 1
Subacute sinusitis: Symptoms lasting 4 to 8 weeks, representing unresolved acute sinusitis with minimal-to-moderate signs of sinus inflammation 1
Chronic sinusitis: Persistent sinus inflammation for greater than 8 weeks (some sources define as >12 weeks), with abnormal findings on CT or MRI imaging 1, 2
Recurrent sinusitis: Three or more episodes of acute sinusitis per year, potentially caused by different organisms at different times 1
Infectious vs. Non-Infectious Forms
While infection is the most common cause, sinusitis can be non-infectious: 1
Acute bacterial sinusitis should be suspected when upper respiratory symptoms persist beyond 10-14 days or worsen after initial improvement 1, 3
Chronic hyperplastic eosinophilic sinusitis is a non-infectious form marked by eosinophils and mixed mononuclear cells with few neutrophils, often associated with nasal polyps, asthma, and aspirin sensitivity 1
Viral sinusitis accounts for most acute sinus infections, with the majority of patients improving within 2 weeks without antibiotics 2, 4
Common Pitfall
The key clinical distinction is that bacterial infection should only be considered if symptoms worsen or fail to improve within 7-10 days, as most acute sinusitis is viral and self-limited. 2, 4 Overdiagnosis of bacterial sinusitis leads to unnecessary antibiotic use.