When are antibiotics indicated for upper respiratory tract infections (URTI)?

When Are Antibiotics Indicated for Upper Respiratory Tract Infections?

Antibiotics are NOT indicated for nonspecific upper respiratory tract infections (URTIs), common colds, or uncomplicated viral illnesses, as these are predominantly viral and antibiotics provide no benefit. 1 However, antibiotics ARE indicated for specific bacterial URTIs when stringent diagnostic criteria are met: confirmed Group A Streptococcal pharyngitis, acute bacterial sinusitis meeting specific criteria, and acute otitis media. 1

General Principle: Most URTIs Do Not Require Antibiotics

• Most uncomplicated URTIs in adults resolve spontaneously within 1-2 weeks, with most patients feeling better within the first week. 1
• These infections are predominantly viral in origin, and complications such as bacterial rhinosinusitis or bacterial pneumonia are rare. 1
• Purulent nasal discharge and sputum do NOT predict bacterial infection and do not justify antibiotic treatment. 1, 2
• Antibiotic therapy does not decrease symptom duration, lost work time, or prevent complications in nonspecific URTIs. 1

Specific Conditions Where Antibiotics ARE Indicated

1. Group A Streptococcal (GAS) Pharyngitis

Antibiotics are justified ONLY when GAS pharyngitis is confirmed by microbiological testing. 1

• Clinical signs alone cannot reliably diagnose GAS pharyngitis—only rapid antigen tests (RAT) or throat culture are reliable. 1
• A positive RAT confirming GAS etiology justifies antibiotics (Grade A evidence). 1
• A negative RAT with low risk factors for acute rheumatic fever (ARF) does not usually require antibiotic therapy. 1
• In pediatrics, only test if 2 of the following are present: fever, tonsillar exudate/swelling, swollen/tender anterior cervical nodes, absence of cough. 1
• Do not treat empirically without confirmation. 1

High-risk situations requiring culture after negative RAT: 1

• Individual history of ARF
• Age 5-25 years with poor social/hygienic/economic conditions or closed institutions
• Particular bacterial epidemics (rheumatogenic strains)
• History of recurring GAS pharyngitis
• Stays in streptococcal-endemic regions (Africa, West Indies)

2. Acute Bacterial Sinusitis

Antibiotics are indicated for acute bacterial sinusitis ONLY when specific diagnostic criteria are met. 1

Diagnostic criteria requiring antibiotics (must meet ONE of the following): 1, 3

• Worsening symptoms: New or worsening fever, daytime cough, or nasal discharge after initial improvement of viral URI
• Severe symptoms: Fever ≥39°C with purulent nasal discharge for at least 3-4 consecutive days
• Persistent symptoms: Nasal discharge or daytime cough lasting >10 days without improvement

First-line antibiotic therapy is NOT indicated when: 1

• Nasal symptoms remain diffuse, bilateral, and of moderate intensity
• Symptoms include congestion with serous or plain puriform discharge
• Occurring in an epidemic viral context

When acute purulent maxillary sinusitis is established, antibiotic therapy is indicated (Grade B). 1

Antibiotic therapy by anatomic location: 1, 3

• Maxillary sinusitis: Amoxicillin-clavulanate, 2nd/3rd generation cephalosporins (cefuroxime-axetil, cefpodoxime-proxetil), or pristinamycin 1, 3
• Frontal, ethmoidal, or sphenoidal sinusitis: Antibiotics are DEFINITELY indicated due to high risk of complications; consider respiratory fluoroquinolones (levofloxacin, moxifloxacin) 1, 3
• Unilateral maxillary sinusitis with upper unilateral dental infection: Antibiotics indicated 1

Duration: 7-10 days (Grade C), though some cephalosporins effective in 5 days. 1, 3

3. Acute Otitis Media (AOM)

AOM requires middle ear effusion AND signs of inflammation for diagnosis. 1

Diagnostic criteria: 1

• Moderate or severe bulging of tympanic membrane (TM); OR
• Otorrhea not due to otitis externa; OR
• Mild bulging of TM with ear pain or erythema of TM

For strictly defined AOM, antibiotics provide benefit with number needed to treat (NNT) as few as 4 patients to achieve symptom improvement. 1

Critical Pitfalls to Avoid

• Do NOT prescribe antibiotics for common cold, influenza, COVID-19, or laryngitis. 4
• Do NOT use purulent discharge as justification for antibiotics—it does not predict bacterial infection. 1, 2
• Do NOT diagnose acute sinusitis based solely on colored nasal discharge or facial pain without meeting specific criteria. 1
• Do NOT treat pharyngitis empirically without microbiological confirmation of GAS. 1
• Avoid fluoroquinolones as routine first-line therapy—reserve for treatment failures or complicated sinusitis. 1, 3
• Previous antibiotic use is the most important factor in carriage of antibiotic-resistant S. pneumoniae—reducing unnecessary use is critical. 1

Special Populations

Pediatric considerations: 1

• Apply stringent diagnostic criteria for AOM, acute bacterial sinusitis, and streptococcal pharyngitis
• In children below 3 years of age, RAT for pharyngitis is usually not performed as GAS is rarely involved 1
• For pediatric sinusitis, immediate antibiotics indicated in severe acute forms or in children with risk factors (asthma, heart disease, sickle cell disease) 1

Immunocompromised patients or those with significant comorbidities (chronic lung/heart disease) require individualized assessment beyond these guidelines. 1

Algorithm for Clinical Decision-Making

Step 1: Determine if symptoms suggest nonspecific URTI (diffuse symptoms, no prominent sinus/pharyngeal/lower airway findings) → NO antibiotics 1

Step 2: If pharyngeal symptoms prominent → Perform RAT or culture → If positive for GAS → Antibiotics indicated 1

Step 3: If sinus symptoms present → Assess if criteria met (worsening after improvement, severe symptoms ≥3-4 days, or persistent >10 days) → If yes, antibiotics indicated 1

Step 4: If ear symptoms in children → Assess for middle ear effusion + inflammation signs → If AOM confirmed, antibiotics indicated 1

Step 5: Reassess at 3-5 days if antibiotics prescribed—if no improvement, switch to alternative agent 3