When should antibiotics be started for cough and cold symptoms?

When to Start Antibiotics in Cough and Cold

Do not prescribe antibiotics for uncomplicated cough and cold—they provide no benefit, do not prevent bacterial complications, and cause significant adverse effects in adults. 1, 2

The Evidence Against Antibiotics for Common Cold

Antibiotics are ineffective for viral upper respiratory infections and should never be used for the common cold or acute bronchitis. 1 The common cold is caused by viruses in over 90% of cases, and antibiotics do not reduce symptom duration, prevent complications, or improve outcomes. 1, 3, 4

• Patients receiving antibiotics show no improvement in cure rates or symptom persistence compared to placebo (odds ratio 0.95% CI 0.59-1.51). 4
• Adults treated with antibiotics have a 3.6-fold increased risk of adverse effects (95% CI 2.21-5.89). 1
• Routine antibiotic use contributes to antimicrobial resistance without clinical benefit. 1, 5

When Antibiotics ARE Indicated

Reserve antibiotics exclusively for confirmed or highly suspected bacterial complications:

Bacterial Sinusitis (After 10 Days)

• Do not diagnose bacterial sinusitis within the first 10 days of symptoms—87% of patients show sinus abnormalities on CT during viral colds that resolve without antibiotics. 1
• Start antibiotics only when symptoms meet at least one of these criteria: 1
  • Persistent symptoms >10 days without improvement
  • Severe symptoms (fever >39°C AND purulent nasal discharge or facial pain) for ≥3 consecutive days
  • "Double sickening" pattern (initial improvement followed by worsening after 5 days)

Suspected Pneumonia

Clinical indicators requiring chest radiograph and potential antibiotics: 1

• Cough with dyspnea, pleuritic chest pain, fever ≥38°C, tachypnea, and new focal chest examination findings (crackles, diminished breath sounds, dullness to percussion)
• Absence of runny nose increases pneumonia likelihood 1
• C-reactive protein ≥30 mg/L strengthens pneumonia diagnosis 1
• Obtain chest radiograph before starting antibiotics when possible 1
• Use empiric antibiotics per local guidelines only when imaging cannot be obtained 1

Pertussis (Whooping Cough)

• Macrolide antibiotics within the first few weeks reduce transmission and diminish coughing paroxysms 1
• Isolate patients for 5 days from treatment start 1

Critical Timeframe: The First Week Rule

Clinical judgment is required during the first week, but bacterial infection should not be assumed. 1 Symptoms, signs, and even imaging abnormalities are indistinguishable between viral and bacterial causes during this period. 1

• 21% of patients have persistent sinus abnormalities at days 13-20 that resolve without treatment 1
• 25% of patients continue having cough and postnasal drainage at day 14—this is normal viral course, not bacterial infection 1, 6

Common Pitfalls to Avoid

Do not prescribe antibiotics based on:

• Symptom duration alone within 10 days 1
• Colored (green or yellow) sputum—this does not indicate bacterial infection 7
• Patient or family pressure for antibiotics 1
• Fever alone without other bacterial indicators 1
• Radiographic sinus abnormalities within the first week 1

The presence of purulent nasal discharge alone does not warrant antibiotics unless accompanied by severe symptoms or prolonged duration. 1, 4

What to Do Instead: Symptomatic Management

Provide effective symptomatic treatment rather than antibiotics: 6, 8

• First-generation antihistamine-decongestant combinations (brompheniramine + pseudoephedrine) for congestion and rhinorrhea 1, 6
• NSAIDs (naproxen or ibuprofen) for pain, fever, and malaise 1, 6, 8
• Zinc lozenges ≥75 mg/day if started within 24 hours of symptom onset 6, 8

Educate patients that:

• Cold symptoms last 7-10 days, with 25% lasting up to 14 days 6, 8
• This prolonged course is normal and does not indicate bacterial infection 6
• Antibiotics will not help and may cause harm 1, 2

Algorithm for Antibiotic Decision-Making

1. Days 0-10: No antibiotics unless pneumonia suspected (obtain chest X-ray) 1
2. After day 10: Consider antibiotics only if symptoms persist without ANY improvement AND meet bacterial sinusitis criteria 1
3. Any time: If "double sickening" pattern or severe symptoms (fever >39°C + purulent discharge + facial pain ≥3 days), consider bacterial sinusitis 1
4. Pneumonia suspected: Obtain chest radiograph; start antibiotics only if confirmed or imaging unavailable 1