Applied Evidence

Acute rhinosinusitis: When to prescribe an antibiotic

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Yes, the majority of antibiotics prescribed for acute rhinosinusitis are unnecessary, but when should you prescribe one and which one(s) should you use?


› Reserve antibiotics for patients who meet diagnostic criteria for acute bacterial rhinosinusitis (ABRS). Patients must have purulent nasal drainage that is accompanied by either nasal obstruction or facial pain/pressure/fullness and EITHER symptoms that persist without improvement for at least 10 days OR symptoms that worsen within 10 days of initial improvement (“double sickening”). A

› Offer watchful waiting and delay antibiotics for up to 7 days after diagnosing ABRS in a patient if adequate access to follow-up is available; otherwise, treat with amoxicillin (with or without clavulanate) for 5 to 10 days. A

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series



An estimated 30 million cases of acute rhinosinusitis (ARS) occur every year in the United States.1 More than 80% of people with ARS are prescribed antibiotics in North America, accounting for 15% to 20% of all antibiotic prescriptions in the adult outpatient setting.2,3 Many of these prescriptions are unnecessary, as the most common cause of ARS is a virus.4,5 Evidence consistently shows that symptoms of ARS will resolve spontaneously in most patients and that only those patients with severe or prolonged symptoms require consideration of antibiotic therapy.1,2,4,6 Nearly half of all patients will improve within 1 week and two-thirds of patients will improve within 2 weeks without the use of antibiotics.7 In children, only about 6% to 7% presenting with upper respiratory symptoms meet the criteria for acute bacterial rhinosinusitis (ABRS),8 which we’ll detail in a bit. For most patients, treatment should consist of symptom management.5

But what about the minority who require antibiotic therapy? This article reviews how to evaluate patients with ARS, identify those who require antibiotics, and prescribe the most appropriate antibiotic treatment regimens.

Diagnosis: Distinguishing viral from bacterial disease

ARS is defined as the sudden onset of purulent nasal discharge plus either nasal blockage or facial pressure/pain lasting < 4 weeks.3,9 Additional signs and symptoms may include postnasal drip, a reduced sense of smell, sinus tenderness to palpation, and maxillary toothaches.10,11

ARS may be viral or bacterial in etiology, with the most common bacterial organisms being Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.1,3,5 The most common viral causes are influenza, parainfluenza, and rhinovirus. Approximately 90% to 98% of cases of ARS are viral6,11; only about 0.5% to 2% of viral rhinosinusitis episodes are complicated by bacterial infection.1,10-12

Diagnose ABRS when symptoms of ARS fail to improve after 10 days or symptoms of ARS worsen within 10 days after initial improvement (“double sickening”).1,11 Symptoms that are significantly associated with ABRS are unilateral sinus pain and reported maxillary pain. The presence of facial or dental pain correlates with ABRS but does not identify the specific sinus involved.1

Approximately 90% to 98% of cases of acute rhinosinusitis are viral; only about 0.5% to 2% of viral rhinosinusitis episodes are complicated by bacterial infection.

There isn’t good correlation between patients saying they have sinusitis and actually having it.13 A 2019 meta-analysis by Ebell et al14 reported that based on limited data, the overall clinical impression, fetid odor on the breath, and pain in the teeth are the best individual clinical predictors of ABRS.

As recommended by the Infectious Disease Society of America (IDSA), a diagnosis of ABRS is also reasonable in patients who present with severe symptoms at the onset.6 Although there is no consensus about what constitutes “severe symptoms,” they are often described as a temperature ≥ 102°F (39°C) plus 3 to 4 days of purulent nasal drainage.1,4,6

Continue to: Additional symptoms of ABRS may include...


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