Acute bronchitis is the most common diagnosis for which antibiotics are inappropriately prescribed. The evidence is unambiguous: antibiotics do not shorten the course, reduce complications, or prevent pneumonia. The clinical decision is not which antibiotic to use — it is whether this is bronchitis or pneumonia.
CLINICAL PRINTABLE
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A one-page Acute Bronchitis clinical reference is on the way.
1 · Recognition
- Acute bronchitis: acute cough (typically 1–3 weeks) with or without sputum production, in a patient without pneumonia. May be preceded by URI symptoms. Cough is the dominant symptom.
- Causative organisms: >90% viral (rhinovirus, coronavirus, influenza, parainfluenza, RSV, adenovirus). Bacterial causes are rare: Bordetella pertussis, Mycoplasma pneumoniae, Chlamydophila pneumoniae account for <10% of cases.
- Vital signs in acute bronchitis: temperature <38°C (or low-grade), heart rate <100 bpm, respiratory rate <24 breaths/min, oxygen saturation normal. Abnormal vital signs should prompt evaluation for pneumonia.
- Pertussis (whooping cough): paroxysmal cough with inspiratory whoop, post-tussive vomiting, cough lasting >2 weeks. Consider in unvaccinated patients, household contacts of confirmed cases, or prolonged cough with paroxysms. Nasopharyngeal PCR for diagnosis.
- Cough duration: acute bronchitis cough typically lasts 2–3 weeks but can persist up to 6 weeks. Patients should be counseled that prolonged cough is expected — this is the most common reason for inappropriate antibiotic prescribing.
2 · Differential / Mimics
Community-acquired pneumonia
Fever >38°C, tachycardia, tachypnea, hypoxia, or focal lung findings on exam. Chest X-ray shows infiltrate. Requires antibiotic treatment. The key distinction from bronchitis.
Asthma exacerbation
Wheezing, dyspnea, chest tightness, reduced peak flow. History of asthma or atopy. Responds to bronchodilators. Acute bronchitis can trigger asthma exacerbation in known asthmatics.
COPD exacerbation
Increased dyspnea, cough, and sputum production in a patient with known COPD. May warrant antibiotics (azithromycin or doxycycline) and systemic corticosteroids — different from acute bronchitis in a healthy patient.
Pertussis
Paroxysmal cough with whoop, post-tussive vomiting, cough >2 weeks. Treat with azithromycin to reduce transmission even if symptoms are established. Notify public health.
3 · Treatment Pathway
Acute bronchitis — no antibiotics
Antibiotics are NOT indicated for acute bronchitis in otherwise healthy adults. Multiple RCTs and meta-analyses show no benefit in symptom duration, severity, or complication prevention. Antibiotic prescribing drives resistance and adverse effects without benefit.
Symptomatic management
Honey for cough (adults and children >1 year). Dextromethorphan or guaifenesin for cough suppression/expectoration. NSAIDs or acetaminophen for fever and myalgia. Avoid codeine-containing cough suppressants in children.
Bronchodilators for wheezing
Albuterol inhaler for patients with wheezing or bronchospasm during acute bronchitis — reduces cough duration in patients with airflow obstruction. Not routinely indicated for all patients.
Pertussis — antibiotic treatment
Azithromycin 500 mg day 1, then 250 mg days 2–5 (or clarithromycin or TMP-SMX). Antibiotics reduce transmission and severity if started in the catarrhal phase — limited benefit in the paroxysmal phase but still recommended to reduce spread. Treat household contacts prophylactically.
Patient communication
Counsel patients that cough will last 2–3 weeks (sometimes up to 6 weeks). Antibiotics will not shorten the course. Provide a specific return-precaution plan: fever >38.5°C, dyspnea, hemoptysis, or symptoms worsening after day 10 warrant re-evaluation.
4 · Expected Response
- Cough duration: median 18 days. Patients should be counseled that 2–3 weeks of cough is the expected course — this prevents unnecessary return visits and antibiotic requests.
- Fever and systemic symptoms resolve within 3–5 days. Persistent or worsening fever after day 5 should prompt re-evaluation for pneumonia or secondary bacterial infection.
- Patients who receive a clear explanation of the expected course and a specific return plan are less likely to return for antibiotics — communication is the intervention.
5 · Escalation
- Pneumonia: fever >38°C, tachycardia, tachypnea, hypoxia, or focal lung findings — chest X-ray and antibiotic treatment. Do not treat presumed pneumonia without imaging confirmation in outpatient settings when the diagnosis is uncertain.
- Hemoptysis: blood-streaked sputum may occur with acute bronchitis, but frank hemoptysis warrants evaluation for malignancy, TB, or pulmonary embolism.
- Cough >3 weeks (subacute) or >8 weeks (chronic): evaluate for pertussis, asthma, GERD, post-nasal drip, ACE inhibitor use, or malignancy. Chest X-ray for chronic cough.
- Immunocompromised patients or those with significant comorbidities: lower threshold for chest imaging and antibiotic treatment — atypical presentations are more common.
Apply It · Change One Detail
APPLY IT
A 28-year-old healthy woman presents with 5 days of cough productive of yellow-green sputum, mild sore throat, and low-grade fever of 37.8°C. Lung exam is clear. Oxygen saturation is 98%. This is acute bronchitis. The yellow-green sputum does not indicate bacterial infection — it reflects neutrophil activity in a viral infection. Antibiotics are not indicated. Symptomatic management and counseling that the cough will last 2–3 weeks is the appropriate response.
CHANGE ONE DETAIL
Change one detail — the same patient has a fever of 39.2°C, heart rate of 108 bpm, and dullness to percussion with decreased breath sounds at the right base. This is pneumonia until proven otherwise. Chest X-ray is indicated. If an infiltrate is confirmed, antibiotic treatment for community-acquired pneumonia is appropriate.
Bottom Line
Acute bronchitis is almost always viral. Antibiotics do not shorten the course. The clinical decision is not which antibiotic to use — it is whether this is bronchitis or pneumonia.
EVIDENCE & REFERENCES
- Smith SM, et al. Antibiotics for acute bronchitis. Cochrane Database Syst Rev. 2017;6:CD000245. doi:10.1002/14651858.CD000245.pub4
- Harris AM, et al. Appropriate antibiotic use for acute respiratory tract infection in adults. Ann Intern Med. 2016;164(6):425-434. doi:10.7326/M15-1840