What is bronchitis?

Bronchitis is inflammation of the bronchial mucosa — the lining of the airways that deliver air into the lungs. When the bronchi become inflamed and produce excess mucus, people develop cough, phlegm production, wheeze, and sometimes breathlessness. Bronchitis is commonly classified into two main types:

• Acute bronchitis: a short-term infection usually caused by viruses; symptoms typically last a few days to a few weeks.
• Chronic bronchitis: a form of chronic obstructive pulmonary disease (COPD) defined clinically by a productive cough for at least three months per year over two consecutive years. Smoking is the leading cause.

How common is bronchitis and who is at risk?

Acute bronchitis is very common — millions of cases occur annually, particularly during viral respiratory infection seasons. Chronic bronchitis is a major component of COPD and is prevalent among current and former smokers.

Risk factors include:

• Active cigarette smoking (strongest risk factor for chronic bronchitis)
• Exposure to secondhand smoke and indoor or outdoor air pollution
• Frequent viral respiratory infections (children and older adults)
• Occupational exposures (dusts, chemical fumes)
• Impaired immunity (e.g., HIV, chronic diseases)

Causes of bronchitis

The underlying causes depend on the type:

Acute bronchitis

Most cases are viral (influenza, respiratory syncytial virus, rhinovirus, coronavirus strains, adenovirus). Bacterial causes are less frequent but can occur, especially in people with underlying lung disease or following influenza.

Chronic bronchitis

Chronic bronchitis is typically caused by long-term irritation and injury to the bronchial lining:

• Tobacco smoke: the dominant cause worldwide.
• Air pollution: long-term exposure to particulate matter and chemical pollutants.
• Occupational exposures: dust, fumes, chemicals in certain workplaces.
• Repeated infections: contribute to ongoing airway inflammation.

Symptoms and clinical presentation

Acute bronchitis

Typical symptoms develop over several days and include:

• Persistent cough that may be dry initially and later productive (with sputum)
• Sputum production: clear, white, yellow, or green — color alone does not always indicate bacterial infection
• Wheeze or chest tightness
• Low-grade fever (more common with viral infections)
• Fatigue and malaise
• Sore throat, nasal congestion often precede bronchitic symptoms

Most symptoms improve within 7–14 days, but the cough can linger for several weeks as airway inflammation resolves.

Chronic bronchitis

People with chronic bronchitis typically report:

• A productive cough most days for at least three months per year for two consecutive years
• Frequent exacerbations with increased cough, sputum, and shortness of breath
• Reduced exercise tolerance and progressive breathlessness over time

When to see a doctor — warning signs

Seek urgent medical evaluation if you experience any of the following:

• High fever (≥39°C / 102°F) or fever lasting more than a few days
• Shortness of breath at rest or rapidly worsening breathlessness
• Chest pain, especially pleuritic chest pain (sharp pain when breathing)
• Confusion, severe dizziness, or fainting
• Coughing up blood (hemoptysis)
• Symptoms lasting more than 3 weeks or recurring frequently

People with severe chronic lung disease, heart disease, or compromised immunity should seek care earlier.

How bronchitis is diagnosed

Diagnosis begins with a careful history and physical exam. Clinicians look for signs of lower respiratory tract infection and assess the likelihood of pneumonia or asthma/COPD exacerbation.

Clinical evaluation

• Auscultation of the lungs for wheeze, rhonchi, or crackles
• Assessment of oxygenation (pulse oximetry)
• Consideration of risk factors (smoking, occupational exposures)

When tests are used

Most uncomplicated acute bronchitis is diagnosed clinically and does not require imaging. Investigations may be ordered if the diagnosis is uncertain or severe:

• Chest X-ray: to exclude pneumonia or other lung pathology when fever, tachypnea, low oxygen saturation, or focal exam findings are present.
• Sputum testing: rarely necessary; used if concern for bacterial infection or in severe cases.
• Pulmonary function tests (spirometry): helpful if coexisting asthma or COPD is suspected.
• Blood tests (CBC): may show leukocytosis in bacterial infection or be normal in viral illness.

Treatment: Evidence-based approach

Treatment depends on the cause, severity, and whether the bronchitis is acute or chronic. Evidence supports conservative management for most cases of acute bronchitis, as antibiotics usually provide minimal benefit when the cause is viral.

Acute bronchitis — conservative care

• Supportive care: rest, hydration, and avoidance of smoke and pollutants.
• Symptom relief: over-the-counter analgesics (acetaminophen or ibuprofen) for fever and body aches; throat lozenges if sore throat.
• Cough management: honey (for adults and children >1 year), warm fluids, humidification, and short-term use of cough suppressants if cough interferes with sleep.
• Bronchodilators: inhaled bronchodilators (e.g., short-acting beta-agonists) may help patients with wheeze or underlying reactive airways disease.

Most healthy adults recover without antibiotics. Antibiotics are reserved for suspected bacterial infections, patients with chronic lung disease, or those at high risk of complications.

Chronic bronchitis — long-term management

• Smoking cessation: the single most important intervention to slow disease progression.
• Bronchodilators: long-acting bronchodilators improve symptoms and reduce exacerbations in COPD-related chronic bronchitis.
• Inhaled corticosteroids: considered in patients with frequent exacerbations or significant airflow obstruction.
• Pulmonary rehabilitation: exercise training, education, and support improve function and quality of life.
• Vaccination: annual influenza vaccine and pneumococcal vaccination per guidelines to reduce respiratory infections.
• Antibiotics during exacerbations: used when increased sputum purulence, volume, and dyspnea suggest bacterial infection.

Medications and special treatments

• Mucolytics: agents that thin mucus may help some patients produce sputum more easily.
• Oxygen therapy: for hypoxemic patients with chronic respiratory failure.
• Systemic corticosteroids: short courses are used for severe exacerbations in COPD or asthma overlap.

Home care and symptom relief

For most acute bronchitis cases, safe and effective home care measures include:

• Hydration: drinking fluids looses mucus and supports recovery.
• Humidified air: showers, humidifiers, or steam inhalation can soothe airways.
• Warm fluids: soups and teas can relieve throat irritation.
• Rest and gradual return to activity: allow the body to heal; avoid heavy exertion while symptomatic.
• Avoidance of irritants: stay away from smoke, strong perfumes, and polluted environments.
• Hand hygiene and isolation: minimize spread to others during viral illness.

Prevention strategies

Reducing the risk of bronchitis and exacerbations involves both personal and public health measures:

• Quit smoking: the most effective individual action to prevent chronic bronchitis.
• Vaccination: influenza and pneumococcal vaccines reduce the risk of respiratory infections that can cause or complicate bronchitis.
• Occupational protection: use masks and ventilation where dust/fume exposure is present.
• Good hygiene: handwashing and respiratory etiquette limit viral spread.
• Control indoor air quality: reduce exposure to secondhand smoke and household pollutants.

Complications and when bronchitis is serious

While acute bronchitis is usually self-limited, complications can occur — especially in older adults, people with chronic lung disease, or those with weakened immune systems:

• Pneumonia: an infection of the lung tissue that requires prompt treatment.
• Exacerbation of chronic lung disease: worsening COPD with reduced lung function.
• Respiratory failure: rare but possible in severe cases with pre-existing lung disease.
• Secondary bacterial infection: may prolong illness and require antibiotics.

Special considerations: children, elderly and people with COPD or asthma

Children

Bronchitis in children is usually viral and often follows an upper respiratory infection. Watch for difficulty breathing, poor feeding, high fever, or dehydration — seek care promptly.

Elderly

Older adults may present atypically and are at higher risk for complications like pneumonia. Early medical evaluation and pulse oximetry are often indicated.

People with COPD or asthma

Bronchitis exacerbations in these populations require prompt treatment to avoid hospital admission. Action plans, quick-relief inhalers, and early antibiotics or steroids may be part of management as advised by a clinician.

Frequently Asked Questions (FAQs)

Practical tips and clinical takeaways

• Most acute bronchitis is viral — focus on supportive care and symptom relief.
• A careful clinical assessment identifies patients needing further testing to exclude pneumonia or other complications.
• For chronic bronchitis, smoking cessation and pulmonary rehabilitation are cornerstone therapies.
• Vaccination (influenza and pneumococcal) reduces infection-related complications.
• Seek urgent care for severe or worsening symptoms, especially in vulnerable populations.

References & further reading

For clinicians and patients, reliable resources include: the Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), American Thoracic Society (ATS), Global Initiative for Chronic Obstructive Lung Disease (GOLD), and peer-reviewed medical literature. For personalized medical advice, consult your healthcare provider.