The prevalence of a bacterial infection during acute rhinosinusitis is estimated to be 2%–10%, whereas viral causes account for 90%–98%. Management of viral rhinosinusitis is primarily focused on symptomatic relief, which may include use of intranasal corticosteroids, analgesics, nasal saline rinses, oral or topical decongestants, and mucolytics. Antibiotics are ineffective for viral illness and do not provide direct symptom relief. Despite this, 82% of Canadian patients diagnosed with acute sinusitis received a prescription for antibiotics. Differentiating viral rhinosinusitis from acute bacterial rhinosinusitis (ABRS) is challenging because the symptoms are overlapping, but is critical to avoid inappropriate antibiotic prescriptions.
The “PODS” clinical criteria suggest ABRS with two or more of facial Pain/pressure/fullness, nasal Obstruction, nasal purulence/discoloured postnasal Discharge, decreased/absent Smell that persist for more than 7-10 days (Canadian Clinical Practice Guidelines for Acute and Chronic Rhinosinusitis for full details). A bacterial infection is so unlikely prior to this timeframe that antibiotics generally should be avoided unless symptoms have persisted for at least 7 days.
In patients who meet the criteria for ABRS with mild or moderate symptoms, intranasal corticosteroids alone are often sufficient. Antibiotics can be considered for patients with severe symptoms or those who fail a 72 hour trial of intranasal corticosteroids after the diagnosis of ABRS* has been made.
*This table outlines how ABRS diagnosis requires the presence of at least 2 persistent or worsening symptoms.
Sources:
Gwaltney JM Jr., et al. Acute Community‐Acquired Bacterial Sinusitis: The Value of Antimicrobial Treatment and the Natural History. Clin Infect Dis. 2004 Jan 15;38(2):227-33. Epub 2003 Dec 19. PMID: 14699455.
Desrosiers M, et al. Canadian Clinical Practice Guidelines for Acute and Chronic Rhinosinusitis. [Internet]. 2011 February [cited 2018 July].
Rosenfeld RM, et al. Clinical practice guideline (update): Adult Sinusitis Executive Summary. Otolaryngol Head Neck Surg. 2015 Apr;152(4):598-609. PMID: 25833927.
Finley R, et al. Human Antimicrobial Use Report [Internet]. Updated 2015 Nov 17 [cited 2018 July].