Bronchitis risk factors: acute and chronic

What bronchitis is

Bronchitis develops when the airways in the lungs, called bronchial tubes, become inflamed and cause coughing, often with mucus. It can be acute (short-term) or chronic (long-term) (NHLBI).

• Acute bronchitis is very common, usually results from an infection and may be contagious. Most people recover after a few days or weeks (NHLBI). MedlinePlus also calls it a chest cold, and notes the cough can last for several weeks after the infection is gone (MedlinePlus).
• Chronic bronchitis is defined as lasting at least three months and returning at least two years in a row. The airway lining stays inflamed, which leads to swelling, more mucus and harder breathing (NHLBI). It is a type of COPD (chronic obstructive pulmonary disease); the other main type is emphysema, and most people with COPD have both (MedlinePlus).

What raises the chance of acute bronchitis

Acute bronchitis is usually caused by airway inflammation from viral infections, such as the cold, influenza (flu), respiratory syncytial virus (RSV) or COVID-19 viruses. Occasionally a bacterial infection causes it (NHLBI).

MedlinePlus says (MedlinePlus):

• the same viruses that cause colds and the flu often cause acute bronchitis, and they spread through the air when people cough or through physical contact, for example on unwashed hands;
• being exposed to tobacco smoke, air pollution, dust, vapors and fumes can also cause it;
• less often, bacteria cause it.

Risk factors for chronic bronchitis

NHLBI lists these risk factors (NHLBI):

• cigarette smoking, or exposure to secondhand smoke;
• older age;
• exposure to fumes or certain kinds of dust;
• a family history of COPD;
• a history of respiratory diseases such as asthma, cystic fibrosis or bronchiectasis;
• gastroesophageal reflux disease (GERD).

MedlinePlus adds detail (MedlinePlus):

• Smoking is the main risk factor. Up to 75% of people who have chronic bronchitis smoke or used to smoke. In the United States, cigarette smoke is the main cause; pipe, cigar and other tobacco smoke can also cause it, especially if inhaled.
• Long-term exposure to other lung irritants, such as secondhand smoke, air pollution, and chemical fumes and dusts from the environment or workplace.
• Age: most people with chronic bronchitis are at least 40 years old when their symptoms begin.
• Genetics: including alpha-1 antitrypsin deficiency, a genetic condition that rarely plays a role. Smokers are also more likely to get chronic bronchitis if they have a family history of COPD.

NHLBI notes that chronic bronchitis does not increase the risk of getting COVID-19, but it does increase the risk of complications after getting COVID-19 (NHLBI).

Symptoms

NHLBI says the symptoms are the same for acute and chronic bronchitis: cough with mucus, chest pain, tiredness, a low fever below 100.4 degrees Fahrenheit, shortness of breath and wheezing. Acute symptoms clear on their own after 2 to 3 weeks; with chronic bronchitis, a productive cough can last three months or longer (NHLBI).

For chronic bronchitis, MedlinePlus says there may be no symptoms or only mild ones at first, getting more severe as the disease gets worse. Some people get frequent respiratory infections such as colds and the flu, and in severe cases it can cause weight loss, weakness in the lower muscles, and swelling in the ankles, feet or legs (MedlinePlus).

Diagnosis

A provider will do a physical exam and ask about your history and symptoms, and may order a blood test to look for infection or a chest X-ray. These tests matter because cough is a symptom of many other conditions, such as pneumonia, COVID-19, GERD and asthma. Pneumonia includes other symptoms like a high fever (100.4 degrees or above), fast breathing and a higher heart rate. NHLBI adds that two of three people who had bronchitis at least twice in five years also had asthma (NHLBI). For chronic bronchitis, tests can include lung function tests, a chest x-ray or CT scan, and blood tests (MedlinePlus).

Treatment

Acute bronchitis often goes away on its own. Providers typically prescribe antibiotics only if they find a bacterial infection (NHLBI), and MedlinePlus notes antibiotics won't help if the cause is viral (MedlinePlus). If you take prescribed medicines or have other diseases, talk to your healthcare provider before taking over-the-counter medicines (NHLBI).

There is no cure for chronic bronchitis, but treatment can help symptoms and slow the disease. MedlinePlus lists quitting smoking (the most important step), avoiding secondhand smoke and other lung irritants, bronchodilator medicines, flu and pneumococcal vaccines, oxygen therapy for severe disease with low blood oxygen, pulmonary rehabilitation, and a lung transplant as a last resort (MedlinePlus).

Lowering the chance of bronchitis

NHLBI says these steps may prevent bronchitis or lower the chance of getting it again (NHLBI):

• quit smoking if you smoke (see our quit smoking help check);
• avoid fumes, air pollution and secondhand smoke;
• get the flu shot every year;
• get the pneumonia vaccine when appropriate, based on your age or risk factors;
• get COVID-19 vaccines at the recommended times.

Since smoking causes most cases of chronic bronchitis, MedlinePlus says the best way to prevent it is to not smoke, and to try to avoid lung irritants such as secondhand smoke, air pollution, chemical fumes and dusts (MedlinePlus).

Viruses also cause most sinus infections, CDC says, and it lists a previous cold, seasonal allergies and smoking or secondhand smoke as its risk factors (CDC). See our sinusitis risk factors guide.

Common questions

Is bronchitis contagious?

Acute bronchitis usually results from an infection and may be contagious (NHLBI); the viruses that cause it spread through the air when people cough or through physical contact (MedlinePlus).

Is chronic bronchitis the same as COPD?

Chronic bronchitis is a type of COPD. The other main type is emphysema, and most people with COPD have both (MedlinePlus).

Can you get chronic bronchitis without smoking?

Smoking is the main risk factor, but long-term exposure to other lung irritants such as secondhand smoke, air pollution, and chemical fumes and dusts, as well as genetics such as alpha-1 antitrypsin deficiency, can also play a role (MedlinePlus).