Is inflammation or infection of the sinuses referred to as sinusitis?

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.