Acute Bronchitis: Symptoms, Causes & Treatment

Acute bronchitis is a self-limiting inflammatory condition of the bronchi — the large airways connecting the trachea to the lungs — and ranks among the most common reasons adults seek medical care. Viral pathogens account for 90–95% of cases: influenza A and B, parainfluenza, rhinovirus, coronavirus, adenovirus, and respiratory syncytial virus (RSV). Bacterial causes (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bordetella pertussis) account for fewer than 10% of episodes. Because the etiology is overwhelmingly viral, antibiotics are inappropriate for most cases and do not shorten illness duration.

The clinical hallmark is an acute cough lasting 1–3 weeks, often preceded by upper respiratory prodrome (rhinorrhea, sore throat, low-grade fever, malaise). Sputum production is common; its color — ranging from clear to yellow or green — does not reliably indicate bacterial infection and should not trigger antibiotic prescription. Chest discomfort, mild dyspnea, and wheezing from bronchospasm may accompany cough. Importantly, cough may persist up to three months as the bronchial epithelium heals — this protracted cough does not imply treatment failure or ongoing infection.

Management is supportive: rest, adequate hydration, antipyretics for fever, and antitussives or expectorants for symptom relief. Inhaled bronchodilators benefit patients with underlying airway hyperreactivity or audible wheezing. Smokers, the elderly, and immunocompromised patients carry higher risk of progression to pneumonia, warranting closer follow-up.

• Persistent cough — the cardinal symptom, lasting 1–3+ weeks
• Sputum production (clear, white, yellow, or green — color alone does not indicate bacterial cause)
• Chest tightness or soreness with coughing
• Low-grade fever, malaise, and fatigue
• Mild wheezing or shortness of breath from bronchospasm
• Preceding upper respiratory symptoms: runny nose, sore throat

• Respiratory viruses (influenza, parainfluenza, rhinovirus, adenovirus, RSV) — responsible for 90–95% of cases
• Atypical bacteria (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bordetella pertussis — whooping cough)
• Inhalation of irritants: tobacco smoke, air pollution, occupational dusts and chemicals
• Underlying airway disease (asthma, COPD) increasing susceptibility and severity

Diagnosis is clinical in most cases: acute cough with or without sputum following an upper respiratory illness, without signs of pneumonia. Chest X-ray is reserved for patients with high fever, tachycardia, tachypnea, hypoxia, or clinical concern for pneumonia. Rapid influenza testing is useful during peak season; Bordetella pertussis PCR is indicated for paroxysmal or prolonged cough with an epidemiological link. Spirometry may reveal reversible airflow obstruction in those with underlying asthma.

Treatment is primarily supportive: rest, adequate fluid intake, and symptom management. Antibiotics are not recommended for viral acute bronchitis and should be avoided to limit resistance. Antitussives (dextromethorphan) or expectorants (guaifenesin) provide modest symptom relief. Inhaled bronchodilators (salbutamol) benefit patients with wheezing or underlying asthma. Antivirals (oseltamivir) are indicated for confirmed influenza within 48 hours of symptom onset. Humidified air and honey (in adults, not infants) may soothe cough.

• Pneumonia from bacterial superinfection, particularly in the elderly, immunocompromised, or smokers
• Chronic bronchitis in smokers with recurrent episodes
• Triggering or worsening of asthma or COPD exacerbations

• Annual influenza vaccination and Tdap booster (Bordetella pertussis) per immunization schedule
• Smoking cessation — smoking impairs mucociliary clearance and predisposes to recurrent bronchitis
• Frequent handwashing and avoiding close contact with infected individuals
• Reducing exposure to airborne irritants: dust, chemicals, indoor air pollution