Bronchiolitis is a common infection of the lungs' airways, often caused by a virus. It most frequently occurs in infants, commonly between 3 and 6 months of age.

What is it?

  • Bronchiolitis is a common infection of the lungs' airways, often caused by a virus. It most frequently occurs in infants, commonly between 3 and 6 months of age. Typically, bronchiolitis occurs during the autumn and winter months.
  • Bronchiolitis starts out with symptoms similar to those of a common cold but then progresses to coughing and wheezing.
  • Although a child's bout of bronchiolitis may be scary, particularly for parents, symptoms typically last for about a week and then go away. In the meantime, you can take a number of self-help measures to make your child more comfortable. In some cases, especially if your child has an underlying health problem, bronchiolitis can become severe and require hospitalization.


For the first two or three days, the signs and symptoms of bronchiolitis are similar to those of a common cold:

  • Runny nose
  • Stuffy nose
  • Slight fever (may or may not occur)

After this, there may be two or three days of:

  • Wheezing — breathing seems more difficult or noisy when breathing out
  • Rapid or difficult breathing
  • Rapid heartbeat

In otherwise healthy infants, the infection generally goes away by itself in seven to 10 days. If your child was born prematurely or has underlying health problems, such as a heart or lung condition or a weakened immune system, the infection may be more severe and your child may need to be hospitalized.

Severe bronchiolitis may cause your child to have difficulty breathing or develop bluish-looking skin (cyanosis) — a sign that he or she isn't getting enough oxygen. This requires emergency medical care.


  • The windpipe (trachea) is the main airway to your lungs. Within your lungs, the trachea branches off into two main breathing tubes called bronchi, one into your left lung and one into your right. Within each lung, the bronchi branch off into smaller and smaller air-tube passageways, distributing air throughout your lungs. The smallest of these airways are called bronchioles.
  • Bronchiolitis occurs when a virus enters the respiratory system and makes its way to the bronchioles, causing them to become inflamed and swollen. As a result, mucus often collects in these airways, which can make it difficult for air to flow freely through your lungs.
  • In older children and adults, the resulting signs and symptoms are generally mild. But an infant's bronchioles are much narrower than are an adult's and are more easily blocked, leading to greater difficulty breathing.
  • The respiratory syncytial virus (RSV), a common virus, causes most childhood bronchiolitis cases. The rest are caused by other infectious agents, including viruses that cause the flu or the common cold. Severe cases of bronchiolitis may reflect multiple infections, such as a combination of RSV and metapneumovirus.
  • Bronchiolitis is a contagious condition. You contract the infectious virus just like you would a cold or the flu — by inhaling airborne droplets of infected mucus or other respiratory secretions or by touching objects contaminated by these secretions and then touching your eyes or the inside of your nose or mouth. There is no vaccine for most of these viruses.

Risk factors

One of the greatest risk factors for getting bronchiolitis is being younger than 6 months old, because the lungs and immune system aren't yet fully developed. Boys tend to get bronchiolitis more frequently than girls do. Other factors that have been associated with an increased risk of bronchiolitis in children include:

  • Never having been breast-fed — breast-fed babies receive immune benefits from the mother
  • Premature birth
  • An underlying heart-lung condition
  • A depressed immune system
  • Exposure to tobacco smoke
  • Contact with multiple children, such as in a child care setting
  • Having siblings who attend school or child care and bring home the infection


Complications of severe bronchiolitis may include:

  • Increasingly labored breathing
  • Cyanosis, a condition in which the skin appears blue or ashen, especially around the lips, caused by lack of oxygen
  • Dehydration
  • Fatigue
  • Severe respiratory failure

If these occur, your child may need hospitalization. Severe respiratory failure may require insertion of a tube into the trachea (intubation) to assist the child's breathing until the infection is brought under control. Untreated, this can be fatal.

If your infant was born prematurely, has a heart or lung condition, or has a compromised immune system, watch closely for beginning signs of bronchiolitis. The infection may rapidly become severe, and signs and symptoms of the underlying condition may become worse. In such cases, your child will usually need hospitalization to monitor his or her health and provide any necessary care.

Infrequently, bronchiolitis is accompanied by another lung infection such as bacterial pneumonia, which is treated separately. Reinfections with RSV after the initial episode may occur but typically aren't as severe. Repeated episodes of bronchiolitis may precede the development of asthma later in life, but the relationship between the two conditions is unclear.


The doctor will likely listen to your child's lungs with a stethoscope to check for wheezing and prolonged breathing out (exhaling). These may indicate obstructed airflow in the bronchioles. The doctor may consider specific risk factors for bronchiolitis as well.

Sometimes other tests are recommended, including:

  • Chest X-ray. In severe or uncertain cases, your doctor may request that a chest X-ray be taken to visually check for any signs of pneumonia. Your doctor may also check for the presence of a foreign object, such as a peanut or small piece of plastic, that your baby or toddler may have inhaled.
  • Mucus sample test. In addition, your doctor may collect a sample of mucus from your child — using a nasal pharyngeal swab or a suction catheter that's gently inserted into the nose — to test for the virus that may be causing the bronchiolitis.
  • Blood tests. Occasionally, blood tests might be used to check your child's white blood cell count. An increase in white blood cells is usually a sign that your body is fighting an infection. A blood test can also determine whether the level of oxygen has decreased in your child's bloodstream. An alternative test for oxygen levels is an oximeter that fits over the finger. Oxygen is necessary to the functioning of the body's organs, including the brain.

Treatments and drugs

  • You can treat most cases of bronchiolitis at home with self-care steps. Because viruses cause bronchiolitis, antibiotics — which are used to treat infections caused by bacteria — aren't effective against it. If your child has an associated bacterial infection, such as pneumonia, your doctor may prescribe antibiotics for that.
  • In more-severe cases, doctors may prescribe inhaled antiviral drugs, such as ribavirin. However, studies haven't found this drug to be consistently effective.
  • If your child has complications from bronchiolitis, a stay at the hospital may be necessary. At the hospital, your child will likely receive humidified oxygen to maintain sufficient oxygen in the blood, and perhaps fluids through a vein (intravenously) to prevent dehydration.

Lifestyle remedies

Although it may not be possible to shorten the duration of your child's illness, you may be able to relieve some of the symptoms and make your child more comfortable. Here are some tips to consider:

  • Humidify the air. If the air in your child's room is dry, a cool-mist humidifier or vaporizer can moisten the air and help ease congestion and coughing. Be sure to keep the humidifier clean to prevent the growth of bacteria and molds. Keep the room warm but not overheated — too much heat can make the air drier. Another way to humidify the air is to run a hot shower or bath in the bathroom and let it steam up the room. Sitting in the room holding your child for about 15 minutes may help ease a fit of coughing.
  • Keep your child upright. Being in an upright position usually makes breathing easier. Placing your infant in a car seat may help. If you plan to leave your child in a car seat for an extended period of time, such as for a nap, make sure your child's head won't fall forward, which can prevent proper breathing. To do this, place foam wedges or a rolled up blanket on each side of your child's head to keep it safely in place. Also check that the seat has an appropriate slope. This varies with the child's size and age.
  • Have your child drink clear fluids. To prevent dehydration, give your child plenty of clear fluids to drink, such as water, juice or gelatin water. Your child may drink more slowly than usual, due to congestion.
  • Try saline nasal drops to ease congestion. You can purchase these drops over-the-counter (OTC). They're effective, safe and nonirritating, even for children. Instill several drops into one nostril, then immediately use a child-sized nasal suction instrument with a small tube on one end and rubber bulb at the other to clear out the nostril (but don't push the bulb too far in). Repeat the process in the other nostril. If your child is old enough, you might teach your child how to blow his or her nose.
  • Use OTC pain relievers. You can purchase these drops over-the-counter (OTC). They're effective, safe and nonirritating, even for children. Instill several drops into one nostril, then immediately use a child-sized nasal suction bulb to clear out the nostril (but don't push the bulb too far in). Repeat the process in the other nostril. If your child is old enough, you might teach your child how to blow his or her nose.
  • Maintain a smoke-free environment. Smoke can aggravate symptoms of respiratory infections. If a family member smokes, ask him or her to smoke outside of the house and outside of the car.


A baby may develop bronchiolitis after catching a virus from an adult or child who has a common cold. When you have a cold, wash your hands before you touch your baby, and consider wearing a face mask as well. Frequent hand washing in general reduces the spread of viruses that cause bronchiolitis. If your child has bronchiolitis, keep him or her at home until the illness is past to avoid spreading it to others.

These other simple but effective ways can help curb spread of the infection:

  • Limit your child's contact with people who have a fever or cold. If your child is a newborn, especially a premature newborn, avoid exposure to people with colds in the first two months of life.
  • Keep bathroom and kitchen countertops in your home clean. Be especially careful if another family member has a cold. To disinfect the area, you can use a solution of bleach and water made with a tablespoon of bleach per gallon of cool water. Don't mix in any other chemicals, as this can create a toxic chemical reaction. Always store homemade mixtures in a labeled container out of the reach of young children.
  • Use a tissue only once. Discard used tissues promptly, then wash your hands or use alcohol hand sanitizer.
  • Use your own drinking glass. Don't share glasses with others.
  • Be prepared away from home. Keep a waterless hand sanitizer handy for yourself and for your child when you're away from home.
  • Wash hands. Frequently wash your own hands and those of your child.