When should antibiotics be started for an upper respiratory tract infection?

When to Start Antibiotics for Upper Respiratory Tract Infections

Most upper respiratory tract infections are viral and should NOT be treated with antibiotics—antibiotics cause more harm than benefit in these cases and should only be initiated when specific clinical criteria for bacterial infection are met. 1, 2

Do NOT Prescribe Antibiotics For:

• Common cold (viral rhinitis) - antibiotics provide no benefit and increase adverse events 2, 3
• Acute bronchitis in healthy adults - even when fever is present, antibiotics are not indicated 1, 2
• Influenza, COVID-19, or laryngitis - these are viral infections where antibiotics cause harm without benefit 2
• Purulent nasal discharge alone - this does NOT indicate bacterial infection and is commonly seen in uncomplicated viral URIs 3

When Antibiotics ARE Indicated:

Acute Bacterial Rhinosinusitis (ABRS)

Start antibiotics when ANY of these three criteria are met: 4, 1

1. Symptoms persist ≥10 days without improvement - purulent nasal drainage with nasal obstruction, facial pain-pressure-fullness, or both 4, 1

2. Severe symptoms for ≥3 consecutive days - fever ≥39°C (102.2°F) with purulent nasal discharge or facial pain 1, 5

3. "Double worsening" - initial improvement followed by worsening of symptoms within 10 days 4, 1

First-line antibiotic: Amoxicillin-clavulanate for 5-10 days 4, 1

Alternative for penicillin allergy: Doxycycline or respiratory fluoroquinolone (levofloxacin/moxifloxacin) 1

Acute Otitis Media (AOM)

Antibiotics are indicated for: 1, 6

• All children <2 years with confirmed AOM 6
• Children ≥2 years with bilateral AOM, otorrhea, or severe symptoms 6
• Watchful waiting is appropriate for children >2 years without severe symptoms, with reassessment at 48-72 hours 1

First-line antibiotic: Amoxicillin 80-100 mg/kg/day in children <30 kg 6

Streptococcal Pharyngitis

Antibiotics only if rapid strep test or culture is POSITIVE 6, 2

• Do not treat based on clinical suspicion alone 2

First-line antibiotic: Amoxicillin or penicillin V for 10 days 6

Exacerbation of Chronic Bronchitis

Immediate antibiotics only for: 4

• Chronic obstructive bronchitis with chronic respiratory insufficiency (dyspnea at rest and/or FEV1 <35%) 4
• Obstructive chronic bronchitis with ≥2 of 3 Anthonisen criteria: increased dyspnea, increased sputum volume, increased sputum purulence 4

For simple chronic bronchitis: Do NOT start immediate antibiotics; reassess at 2-3 days and only treat if fever >38°C persists beyond 3 days 4

Critical Pitfalls to Avoid:

• Do not use imaging for uncomplicated ARS—diagnosis is clinical 4
• Do not prescribe first-generation cephalosporins (e.g., cephalexin) for respiratory infections—they lack adequate coverage against resistant S. pneumoniae 1
• Do not use macrolides as first-line due to >40% S. pneumoniae resistance in the U.S. 1
• Fever persistence >3 days suggests bacterial superinfection, but associated ENT signs (rhinorrhea, upper airway obstruction) suggest viral etiology 4

Watchful Waiting Strategy:

For uncomplicated ABRS meeting diagnostic criteria, watchful waiting is an option IF: 4

• Assured follow-up is available 4
• Patient understands to start antibiotics if no improvement by 7 days OR worsening at any time 4
• Reassessment occurs at 2-3 days to evaluate therapeutic response 1

However, if symptoms have already persisted >10 days, the watchful waiting window has passed and antibiotics should be initiated. 1

Monitoring After Antibiotic Initiation:

• Reassess at 48-72 hours - fever should resolve within this timeframe for most bacterial URIs 1, 7
• Do not change antibiotics before 72 hours unless significant clinical deterioration or complications develop 1
• Persistent cough after completing antibiotics does NOT constitute treatment failure - cough may continue for weeks 1