Bronchitis is inflammation of the bronchial tubes, the airways that carry air into your lungs. It often causes a cough, sometimes with mucus, and may also cause wheezing, tiredness, or chest discomfort. Acute bronchitis usually follows a respiratory infection and improves over days to weeks. Chronic bronchitis is long-term and is often linked to smoking or ongoing exposure to lung irritants.
What Happens in the Airways During Bronchitis?
The bronchial tubes carry air between your windpipe and lungs. Their inner lining normally helps protect the respiratory system and move mucus, which traps dust and other particles, out of the airways. When this lining becomes inflamed, it swells and may produce extra mucus. The irritation can trigger repeated coughing as the body attempts to clear the airways.
Bronchitis can develop over a short period or persist for much longer. The National Heart, Lung, and Blood Institute explains that bronchitis can be acute or chronic. These forms differ in how long the airway inflammation lasts, what commonly causes it, and how it is managed.
What Are the Two Main Types of Bronchitis?
Acute bronchitis
Acute bronchitis is a short-term inflammation of the bronchial tubes. It often develops during or after a respiratory infection, such as a common cold or the flu. It is sometimes called a chest cold. Most cases improve without specific treatment, although the cough can continue for several weeks after other symptoms have eased. An episode of acute bronchitis does not necessarily mean that a person has an ongoing lung condition.
Chronic bronchitis
Chronic bronchitis involves long-lasting or repeatedly occurring inflammation that produces a persistent cough with mucus. Mayo Clinic describes the usual definition as a mucus-producing cough lasting at least three months, with recurring episodes for at least two consecutive years. Smoking is a major cause, although long-term exposure to other airway irritants can also contribute. Chronic bronchitis is one of the conditions associated with chronic obstructive pulmonary disease (COPD), a group of lung diseases that can make breathing difficult.
What Causes Bronchitis?
The causes depend partly on whether the condition is acute or chronic. Acute bronchitis most often develops because of a viral infection. Chronic bronchitis is more commonly associated with repeated or ongoing exposure to substances that irritate the airways.
- Respiratory viruses: Viruses that cause colds, influenza, respiratory syncytial virus (RSV), and COVID-19 can cause acute bronchitis.
- Tobacco smoke: Smoking and breathing secondhand smoke irritate the airways and are important risk factors, particularly for chronic bronchitis.
- Dust, fumes, and air pollution: Exposure to workplace chemicals, airborne dust, polluted air, and other irritants can inflame the bronchial tubes.
- Bacterial infections: Bacteria can sometimes be involved in acute respiratory illness, although viruses are the usual cause of acute bronchitis.
According to Mayo Clinic's overview of bronchitis causes and risk factors, smoking and exposure to environmental or workplace irritants are important contributors to chronic bronchitis. The condition is not always the result of an infection, so not every form of bronchitis can spread from one person to another.
What Symptoms Can Occur With Bronchitis?
A cough is the main symptom of bronchitis. Other symptoms may occur alongside it, particularly when the condition develops during a respiratory infection. The symptoms and their duration can vary depending on the cause and whether the inflammation is acute or chronic.
- Cough: A persistent or irritating cough that may produce mucus or may be dry.
- Mucus production: Phlegm that can appear clear, white, yellow, or green.
- Chest discomfort: Soreness or discomfort that becomes noticeable during coughing.
- Wheezing: A whistling sound when breathing that can occur when the airways narrow.
- Shortness of breath: A feeling of difficulty getting enough air, particularly if airway irritation affects breathing.
- Other respiratory symptoms: Fatigue, a sore throat, nasal congestion, a runny nose, mild body aches, or a low-grade fever.
The color of mucus alone cannot establish the cause of bronchitis. The Centers for Disease Control and Prevention (CDC) notes that colored mucus does not indicate a bacterial infection in adults with acute uncomplicated bronchitis. Other symptoms and clinical findings are more useful when a healthcare professional evaluates the illness.
Is Bronchitis Contagious?
Acute bronchitis can be contagious when it is caused by a virus. The virus may spread through respiratory droplets or particles released when an infected person coughs, sneezes, or talks. Some respiratory viruses can also spread when a person touches a contaminated surface and then touches their eyes, nose, or mouth.
Chronic bronchitis caused by smoking or environmental irritants is not itself an infectious illness. However, a person with chronic bronchitis can also develop a respiratory infection that may spread to others. Washing hands, covering coughs and sneezes, keeping up with recommended vaccinations, and avoiding close contact with people who are ill can help reduce exposure to respiratory viruses.
How Is Bronchitis Diagnosed?
A healthcare professional usually begins by asking about the cough, when it started, whether it produces mucus, and whether other symptoms have developed. They may also ask about smoking, workplace exposures, previous respiratory illnesses, existing medical conditions, and how symptoms have changed over time. A physical examination commonly includes listening to the lungs and assessing breathing.
According to MedlinePlus, a healthcare professional may recommend additional tests when needed. A chest X-ray, for example, may be considered if pneumonia is a concern. Other tests may be appropriate when the symptoms or medical history suggest another explanation, such as asthma or a different respiratory infection. Testing is not necessary for every uncomplicated case of acute bronchitis.
How Is Bronchitis Treated?
Care for acute bronchitis
Most cases of acute bronchitis improve with time and supportive care. Rest, drinking enough fluids, and using a clean humidifier may help ease discomfort. Warm drinks may soothe an irritated throat, and honey may help relieve cough in adults and children aged one year or older. Honey must not be given to children younger than one year. Avoiding tobacco smoke and other airway irritants can also reduce further irritation.
The CDC's guidance on acute bronchitis explains that antibiotics do not help people recover from a typical viral chest cold. They are not routinely recommended for uncomplicated acute bronchitis. Using them unnecessarily can cause side effects and contribute to antibiotic resistance. If symptoms suggest another illness, such as pneumonia or whooping cough, a healthcare professional may recommend a different approach.
Some nonprescription medicines may temporarily relieve symptoms, but their suitability depends on the person's age, medical history, and other medicines. Children require particular care because some cough and cold products are not recommended at younger ages. A pharmacist or healthcare professional can help determine which options, if any, are appropriate.
Care for chronic bronchitis
Management of chronic bronchitis focuses on reducing airway irritation, improving breathing, and controlling symptoms. Stopping smoking and limiting exposure to secondhand smoke, dust, and fumes are important steps. Depending on the person's condition, a healthcare professional may recommend inhaled medicines, pulmonary rehabilitation, or other treatments used for COPD. Ongoing symptoms need clinical assessment because treatment depends on the underlying lung condition and its effects on breathing.
When Should You Seek Medical Care?
A cough that persists, worsens, or interferes with daily activities deserves medical assessment. Bronchitis can cause symptoms that overlap with other conditions, so it is important not to assume that every persistent cough is due to bronchitis.
Arrange prompt medical evaluation if you have a cough lasting more than three weeks, blood in your mucus, recurring episodes of bronchitis, chest pain, a persistent or high fever, or shortness of breath. People who are pregnant, older adults, and those with heart or lung disease, diabetes, kidney disease, or a weakened immune system may need earlier assessment.
Seek emergency medical help for severe difficulty breathing, gasping that prevents speaking, bluish or unusually pale lips or skin, or sudden confusion. The NHS guidance on bronchitis also highlights the importance of urgent assessment when breathing difficulties or other concerning symptoms occur. For a baby younger than three months, a temperature of 38°C (100.4°F) or higher requires prompt medical attention.
Can Bronchitis Be Prevented?
Not every episode can be prevented, but several everyday measures can lower exposure to respiratory infections and airway irritants. Wash your hands regularly, cover coughs and sneezes, improve indoor ventilation where possible, and follow vaccination recommendations appropriate for your age and health. Avoid smoking and reduce exposure to secondhand smoke, workplace dust, and chemical fumes. If your work involves respiratory irritants, ask about suitable protective measures.
Understanding the difference between acute and chronic bronchitis helps explain why symptoms, likely causes, and treatment approaches can differ. Acute bronchitis is usually a temporary illness, while chronic bronchitis involves ongoing airway problems that may require long-term care. Persistent, worsening, or unusual respiratory symptoms should be evaluated by a healthcare professional.