Bronchiolitis and Infectious Bronchitis

Bronchiolitis (brong-kee-o-LYE-tis) is an infection that causes inflammation of the lung's smaller airways, the bronchioles (BRONG-kee-oles). It is common among very young children, particularly during the winter months. Bronchitis (brong-KYE-tis) is a disease that involves inflammation (irritation and swelling) of the larger airways in the respiratory tract. These airways, called the bronchial (BRONG-kee-ul) tubes or bronchi (BRONGkye), extend from the windpipe to the lungs. Another name for the windpipe is the trachea. Bronchitis and bronchiolitis can result from infection or other causes.

What Are Bronchitis and Bronchiolitis?

In both bronchitis and bronchiolitis, the tissue lining the airways swells, narrowing the air passages and making breathing difficult. The inflamed airways produce large amounts of a thick, slippery substance called mucus, which can clog the air passages and complicate breathing even more. People who have bronchitis and bronchiolitis cough frequently to expel this excess mucus.

Bronchitis and bronchiolitis can also affect the cilia, which are fine, hairlike structures on the surface of the cells lining the airways. Normally, the cilia help cleanse the airways of inhaled particles, but in individuals who have these conditions, the cilia become less able to clear impurities and bacteria from the airways, making it harder for the person to fight off lung infection.

What Causes Bronchitis?

Viral and, sometimes, bacterial infections, can cause bronchitis, but many people get it as the result of smoking or from living or working in areas that have heavy air pollution and/or dust. There are three types of bronchitis: acute bronchitis, chronic (KRAH-nik) bronchitis, and asthmatic bronchitis.

Acute bronchitis

Acute bronchitis comes on quickly and often results from an infection by a virus. Viruses that can cause acute bronchitis are contagious. People can get a viral infection from someone who is infected if they come into contact with that person's respiratory fluids. The virus can also spread from person to person through the air by way of the droplets from a sneeze or cough. Acute bronchitis can also result from an allergy or from inhaling irritating substances in the air, such as smoke from a fire. In all, more than 12 million people have bouts of acute bronchitis every year, and most of them are children under five years of age, who typically get it in winter and early spring. Usually, acute bronchitis lasts about 10 days, but in severe cases, an individual may have a cough that lasts months as the bronchi heal.

Chronic bronchitis

No matter who they are, what their job is, or where they live, people who smoke cigarettes are more likely to experience chronic bronchitis. The American Lung Association reports that the disease develops in more than 9 million people in the United States every year. People with chronic lung disease are also likely to experience chronic bronchitis. Generally, chronic bronchitis is not contagious. It results from persistent or repeated inflammation of the lungs over at least two to three months, which can continue or come and go for years. Individuals with chronic bronchitis typically have a bad cough and restricted airflow because of the excess mucus in their airways.

Asthmatic bronchitis

Asthmatic bronchitis is seen in people with persistent asthma.

What Causes Bronchiolitis?

In the vast majority of bronchiolitis cases, a virus infects the bronchioles, the smallest airways that carry air through the lungs. The virus that most often causes bronchiolitis is called respiratory syncytial virus * (RSV). Other viruses, such as rhinovirus, parainfluenza * virus, influenza A * , and adenovirus * , can also cause bronchiolitis. These viruses are contagious.

Close-up view of the anatomy of the left lung and of one of its bronchial tubes, which is called a bronchus. Healthy bronchi bring air in and out of the lungs, but in people with irritated and inflamed bronchi,

Close-up view of the anatomy of the left lung and of one of its bronchial tubes, which is called a bronchus. Healthy bronchi bring air in and out of the lungs, but in people with irritated and inflamed bronchi, mucus clogs up the inside of the tubes. The inflammation interferes with breathing and causes coughing that often brings up the mucus.
Illustration by Frank Forney. © 2016 Cengage Learning®.
Kicking Butts

When a smoker quits smoking, it takes only 20 minutes to feel better. Statistics from the American Lung Association show the following:

The long-term benefits are encouraging too. After 5 to 15 years, the risk of stroke drops to that of someone who has never smoked. At 10 years after quitting, the risk of lung cancer can become just half of that of a continuing smoker, and the risk of several other smoking-related cancers becomes lower. At 15 years, the likelihood of having a heart attack drops to that of someone who has never smoked at all.

Viral bronchiolitis occurs commonly in late fall, winter, and early spring. It typically affects younger children, with most cases occurring in children two years old or younger. Many may only get bad cold symptoms and nothing more, but others may need hospital care. In fact, bronchiolitis is a leading cause of hospitalizations for children under five years old; more than 100,000 per year occur annually in the United States.

While most bronchiolitis results from viral infection, it sometimes has other causes. These types of noninfectious bronchiolitis may stem from:

What Are the Signs and Symptoms of Bronchitis and Bronchiolitis?

Chronic bronchitis usually is marked by a cough that lasts three months or longer, tightness in the chest, and trouble breathing. Acute bronchitis and bronchiolitis symptoms often mimic those of a cold. Common symptoms include coughing that brings up mucus, wheezing, tiredness, chest pain, a low fever, and difficulty breathing. Individuals who have difficulty breathing should see a doctor immediately to make sure they are getting enough oxygen. Signs of breathing difficulties may be blue skin or lips, very rapid breaths, or a noticeable inward movement (called a retraction) of the muscles between the ribs while breathing. Individuals who cannot drink and hold down fluid should also see a doctor right away. In that case, the doctor may check for signs of dehydration * .

In diagnosing these conditions, a doctor will start by listening to the person's breathing. The doctor may then order either a chest x-ray to check for pneumonia or a lung function test to check for asthma. The doctor may also take a sample of the individual's nasal fluid and ask laboratory technicians to check it for the presence of RSV. They do this with an antigen detection test.

How Are Bronchitis and Bronchiolitis Treated?

Most otherwise healthy people who have bronchitis and bronchiolitis can recover at home. Doctors usually recommend that individuals drink lots of fluids, eat a well-balanced diet, and get plenty of sleep, preferably in a room that has a cool-mist vaporizer or humidifier running to ease breathing. For pain and fever, doctors typically suggest over-the-counter medications such as acetaminophen (Tylenol). For patients with acute bronchiolitis, a doctor may also prescribe bronchodilator drugs to help open the airways. Bronchodilator drugs come either in pill form or in a spray inhaler.

The vast majority of bronchitis and bronchiolitis cases result from viruses, so doctors generally do not prescribe or recommend antibiotics. Although decongestants may seem like a good choice as a way of decreasing the amount of mucus, they often produce unwanted side effects in very young children and should not be given to them. Instead, a parent can clear the mucus from a child's nose with suction from a rubber bulb and saltwater nose drops. Occasionally, children with bronchiolitis, especially those born prematurely or with heart or lung problems, may have to be hospitalized so that they can get extra oxygen and fluids, and if necessary, breathing treatments.

For people who have chronic bronchitis, the best treatments are preemptive measures: abstaining from smoking and avoiding dust, fumes, and cold or dry air. Besides these preventive steps, individuals with chronic bronchitis may get some relief from their symptoms through cough medicine and vaporizers.

What to Expect

Most symptoms of acute bronchitis and bronchiolitis clear up after a few days to a week, but the cough may last several weeks longer while the airways in the lungs heal. Chronic bronchitis symptoms last longer and may never resolve because the damage to the lungs may be permanent. Because of the production of excess mucus, the body's natural reflex will be to cough it up. This cough may come and go for a long time, flaring up, subsiding, and flaring up again.

Occasionally, people with bronchitis and bronchiolitis develop other conditions, which include pnemonia * , apnea * , and respiratory failure * . These are more common among individuals who have heart, lung, or other health problems, and among children who were born prematurely. Children who have had bronchiolitis are more prone to asthma * later in childhood. Chronic bronchitis, by contrast, can lead to heart failure because it makes the heart work harder to compensate for the lack of oxygen. Severe respiratory problems can develop and, in some cases, can result in death.

How Can Bronchitis and Bronchiolitis Be Prevented?

Because the viruses that cause bronchitis and acute bronchiolitis—especially RSV—spread very easily from one person to another, people can reduce their chances of getting the diseases by washing their hands frequently. Parents should also instruct their children not to share drinks or eating utensils with other children. In addition, parents should keep their children home from school if they have either disease so that their children do not infect their classmates. As an added precaution, doctors may suggest infection-preventing immunizations against RSV for certain children who are at high risk of becoming seriously ill from bronchiolitis. These children include premature infants and those with chronic heart or lung disease.

* vaccination * (flu shot) to prevent symptoms from flaring up in response to infection with flu viruses.

See also Chronic Obstructive Pulmonary Disease (COPD) • Common Cold • Influenza • Pneumonia


Books and Articles

“That Nagging Cough,” Harvard Men's Health Watch, September 1, 2010. Available at: (accessed November 23, 2015).

Zanni, Guido R. “Bronchitis: Symptoms and Treatment,” U.S. News and World Report, November 29, 2013. Available at: (accessed November 23, 2015).


MedlinePlus “Bronchitis, Acute.” U.S. National Library of Medicine. (accessed November 23, 2015).


American Lung Association. 55 W Wacker Dr., Suite 1150, Chicago, IL 60601. Toll-free: 800-LUNGUSA. Website: (accessed November 23, 2015).

* respiratory syncytial virus (RES-puh-ruh-tor-e sin-SIH-she-ul), or RSV, is a virus that infects the respiratory tract and typically causes minor symptoms in adults but can lead to more serious respiratory illnesses in children.

* parainfluenza (pair-uh-in-floo-EN-zuh) is a family of viruses that cause respiratory infections.

* influenza A (in-floo-EN-zuh A) is one member of a family of viruses that attacks the respiratory tract.

* adenovirus (ah-deh-no-VY-rus) is a type of virus that can produce a variety of symptoms, including upper respiratory disease, when it infects humans.

* dehydration (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually caused by excessive and unre-placed loss of body fluids, such as through sweating, vomiting, or diarrhea.

* pneumonia (nu-MO-nyah) is inflammation of the lungs.

* apnea (AP-nee-uh) is a temporary cessation of breathing.

* respiratory failure is a condition in which breathing and oxygen delivery to the body are dangerously altered. This may result from infection, nerve or muscle damage, poisoning, or other causes.

* asthma (AZ-mah) is a condition in which the airways of the lungs repeatedly become narrowed and inflamed, causing breathing difficulty.

* influenza (in-floo-EN-zuh), also known as the flu, is a contagious viral infection that attacks the respiratory tract, including the nose, throat, and lungs.

* vaccination (vak-sih-NAY-shun) is giving, usually by an injection, a preparation of killed or weakened germs, or a part of a germ or product it produces, to prevent or lessen the severity of the disease caused by that germ. Also called immunization.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)