How You Get Bronchitis?

Bronchitis happens when the airways in your lungs become inflamed and swollen. Most people get it from the same viruses that cause the common cold or flu. These viruses spread through the air when someone coughs or sneezes, or by touching contaminated surfaces. Bacteria cause a much smaller number of cases. Understanding exactly how you get bronchitis helps you avoid it and know when to see a doctor.

What is bronchitis and how does it start?

Bronchitis is inflammation of the bronchial tubes. These are the passages that carry air to and from your lungs. When they get irritated, they swell up and produce extra mucus. That is what causes the cough and phlegm.

There are two types. Acute bronchitis lasts a few weeks and usually follows a cold or flu. Chronic bronchitis is a long-term condition where the airways stay inflamed for months at a time. It is a form of COPD. The causes are different for each type, so it helps to know which one you are dealing with.

How you get bronchitis from viruses

Viral infections cause about 85 to 95 percent of acute bronchitis cases. The same viruses that give you a cold or the flu can travel down into your bronchial tubes. Once there, they infect the cells lining the airways and trigger inflammation.

The most common viruses involved include rhinovirus, influenza A and B, respiratory syncytial virus, and adenovirus. These are all highly contagious. You catch them the same way you catch a cold. Someone who is infected coughs or sneezes, releasing tiny droplets into the air. You breathe those droplets in. Or you touch a surface the droplets landed on then touch your eyes, nose, or mouth.

The virus does not cause bronchitis immediately. It first causes cold-like symptoms for a few days. Then the infection moves deeper into the chest. That is when the cough starts. The cough is the body trying to clear the extra mucus from the inflamed airways.

Most people with viral bronchitis are contagious for a few days before symptoms start and for as long as they have symptoms. The cough can last for weeks even after you are no longer contagious.

How you get bronchitis from bacteria

Bacterial bronchitis is much less common. Estimates suggest it accounts for less than 10 percent of acute bronchitis cases. When bacteria are the cause, they usually infect people whose immune systems are already weakened or who have underlying lung disease.

Common bacteria involved include Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis which causes whooping cough. These bacteria spread the same way viruses do through respiratory droplets. But they do not cause bronchitis in everyone who is exposed. Most healthy adults fight off the bacteria before they reach the bronchial tubes.

Bacterial bronchitis can also develop as a secondary infection. This happens when a viral infection damages the airways enough that bacteria can move in and multiply. It is one reason why a cold that seems to get better then suddenly gets worse could be a sign of a bacterial infection.

Doctors can usually tell the difference. Viral bronchitis tends to come with clear or white phlegm and does not respond to antibiotics. Bacterial bronchitis often causes yellow or green phlegm and may require antibiotics. But color alone is not a reliable way to tell. Lab tests are more accurate.

What about chronic bronchitis?

Chronic bronchitis is not caused by an infection. It is caused by long-term irritation of the airways. The number one cause is cigarette smoking. Smoking damages the tiny hair-like structures called cilia that line the airways. These cilia normally sweep mucus and debris out of the lungs. When they stop working, mucus builds up and inflammation becomes constant.

Secondhand smoke is also a major cause. People who live with smokers have a higher risk of developing chronic bronchitis even if they never smoke themselves. Occupational exposure to dust, chemical fumes, and air pollution can also cause it over time.

Unlike acute bronchitis, chronic bronchitis does not go away on its own. The damage to the airways is mostly permanent. Treatment focuses on managing symptoms and slowing the progression of the disease.

Can you get bronchitis without an infection?

Yes. Not all bronchitis is caused by germs. Irritants in the air can inflame the bronchial tubes directly. This is sometimes called irritant-induced bronchitis.

Common irritants include tobacco smoke, air pollution, strong chemical fumes from cleaning products or industrial work, and dust. Even cold dry air can trigger bronchitis in some people. The symptoms look the same as infectious bronchitis. You cough, produce phlegm, and feel tightness in your chest.

The difference is that irritant-induced bronchitis is not contagious. You cannot give it to someone else. It also tends to improve quickly once you remove the irritant. If you work in a place with fumes or dust and keep coughing, the cause might be your work environment.

How do you know if you have bronchitis?

The main symptom is a cough that brings up mucus. The mucus can be clear, white, yellow, or green. You may also have a low fever, chest discomfort, shortness of breath, and feeling tired. Symptoms usually start a few days after you catch a cold or flu.

Acute bronchitis typically lasts 10 to 14 days. The worst of the cough usually happens in the first week. But a dry cough can linger for three to four weeks even after the infection clears. That is because the airways need time to heal.

See a doctor if your cough lasts longer than three weeks, if you have a fever above 100.4°F that lasts more than a few days, if you cough up blood, or if you have trouble breathing. These could be signs of pneumonia or another more serious condition.

How to lower your risk of getting bronchitis

The same habits that prevent colds and flu also prevent bronchitis. Wash your hands often with soap and water. Avoid touching your face. Stay away from people who are sick. Get the flu vaccine every year. The flu vaccine does not prevent all cases of bronchitis, but it does prevent the flu which is a common trigger.

If you smoke, quitting is the single most effective thing you can do. Smoking damages the cilia in your airways and makes you more vulnerable to both acute and chronic bronchitis. Even cutting back reduces your risk.

Wear a mask if you work around dust, fumes, or chemicals. Use air filters in your home if you live in an area with poor air quality. Keep your home humidified in dry winter months because dry air can irritate airways.

Common misconceptions about how you get bronchitis

One common myth is that bronchitis is always bacterial and always needs antibiotics. This is not true. Most bronchitis is viral. Antibiotics do not work against viruses. Taking them when you do not need them contributes to antibiotic resistance, which makes future bacterial infections harder to treat.

Another myth is that bronchitis is always contagious. Acute bronchitis from a virus or bacteria is contagious. Chronic bronchitis from smoking or pollution is not. You cannot catch someone’s chronic bronchitis.

Some people believe that getting wet or being in cold weather causes bronchitis. Cold weather does not directly cause bronchitis. It can irritate airways and make symptoms worse if you already have bronchitis. But the infection itself comes from a virus or bacteria, not from being cold.