Skip to main content


Medically reviewed by Last updated on Feb 25, 2023.


Bronchiolitis is a common lung infection in young children and infants. It causes swelling and irritation and a buildup of mucus in the small airways of the lung. These small airways are called bronchioles. Bronchiolitis is almost always caused by a virus.

Bronchiolitis starts out with symptoms much like a common cold. But then it gets worse, causing coughing and a high-pitched whistling sound when breathing out called wheezing. Sometimes children have trouble breathing. Symptoms of bronchiolitis can last for 1 to 2 weeks but occasionally can last longer.

Most children get better with care at home. A small number of children need a stay in the hospital.

Bronchioles and alveoli in the lungs

In your lungs, the main airways, called bronchi, branch off into smaller and smaller passageways. The smallest airways, called bronchioles, lead to tiny air sacs called alveoli.


For the first few days, the symptoms of bronchiolitis are much like a cold:

Later, your child may have a week or more of working harder than usual to breathe, which may include wheezing.

Many infants with bronchiolitis also have an ear infection called otitis media.

When to see a doctor

If symptoms become serious, call your child's health care provider. This is especially important if your child is younger than 12 weeks old or has other risk factors for bronchiolitis — for example, being born too early, also called premature, or having a heart condition.

Get medical attention right away if your child has any of these symptoms:


Bronchiolitis happens when a virus infects the bronchioles, which are the smallest airways in the lungs. The infection makes the bronchioles swollen and irritated. Mucus collects in these airways, which makes it difficult for air to flow freely in and out of the lungs.

Bronchiolitis is usually caused by the respiratory syncytial virus (RSV). RSV is a common virus that infects just about every child by 2 years of age. Outbreaks of RSV infection often happen during the colder months of the year in some locations or the rainy season in others. A person can get it more than once. Bronchiolitis also can be caused by other viruses, including those that cause the flu or the common cold.

The viruses that cause bronchiolitis are easily spread. You can get them through droplets in the air when someone who is sick coughs, sneezes or talks. You also can get them by touching shared items — such as dishes, doorknobs, towels or toys — and then touching your eyes, nose or mouth.

Risk factors

Bronchiolitis usually affects children under the age of 2 years. Infants younger than 3 months have the highest risk of getting bronchiolitis because their lungs and their ability to fight infections aren't yet fully developed. Rarely, adults can get bronchiolitis.

Other factors that increase the risk of bronchiolitis in infants and young children include:


Complications of severe bronchiolitis may include:

If any of these happen, your child may need to be in the hospital. Severe respiratory failure may require that a tube be guided into the windpipe. This helps your child breathe until the infection improves.


Because the viruses that cause bronchiolitis spread from person to person, one of the best ways to prevent infection is to wash your hands often. This is especially important before touching your baby when you have a cold, flu or other illness that can be spread. If you have any of these illnesses, wear a face mask.

If your child has bronchiolitis, keep your child at home until the illness is past to avoid spreading it to others.

To help prevent infection:

Vaccines and medications

There are no vaccines to prevent the most common causes of bronchiolitis — RSV and rhinovirus. But getting a flu shot every year is recommended for everyone older than 6 months.

Infants at high risk of RSV infection, such as those born prematurely or those with a lung condition or a weakened immune system, may be given the medicine palivizumab (Synagis). This medicine can decrease the risk of RSV infections.


Your child's health care provider can usually diagnose bronchiolitis by the symptoms and listening to your child's lungs with a stethoscope.

Tests and X-rays are not usually needed to diagnose bronchiolitis. But your child's provider may recommend tests if your child is at risk of severe bronchiolitis, if symptoms are getting worse or if the provider thinks there may be another problem.

Tests may include:

Your child's provider may look for symptoms of dehydration, especially if your child has been refusing to drink or eat or has been vomiting. Signs of dehydration include dry mouth and skin, extreme tiredness, and making little or no urine.


Bronchiolitis usually lasts for 1 to 2 weeks but symptoms occasionally last longer. Most children with bronchiolitis can be cared for at home with comfort measures. It's important to be alert for problems with breathing that are getting worse. For example, struggling for each breath, not being able to speak or cry because of struggling to breathe, or making grunting noises with each breath.

Because viruses cause bronchiolitis, antibiotics — which are used to treat infections caused by bacteria — don't work against viruses. Bacterial infections such as pneumonia or an ear infection can happen along with bronchiolitis. In this case, your child's health care provider may give an antibiotic for the bacterial infection.

Medicines called bronchodilators that open the airways don't seem to help bronchiolitis, so they usually aren't given. In severe cases, your child's health care provider may try a nebulized albuterol treatment to see if it helps. During this treatment, a machine creates a fine mist of medicine that your child breathes into the lungs.

Oral corticosteroid medicines and pounding on the chest to loosen mucus, a treatment called chest physiotherapy, have not been shown to be effective for bronchiolitis and are not recommended.

Hospital care

A small number of children may need a stay in the hospital. Your child may receive oxygen through a face mask to get enough oxygen into the blood. Your child also may get fluids through a vein to prevent dehydration. In severe cases, a tube may be guided into the windpipe to help breathing.

Lifestyle and home remedies

Though it may not be possible to shorten the length of your child's illness, you may be able to make your child more comfortable. Here are some tips:

Don't use other over-the-counter medicines, except for fever reducers and pain relievers, to treat coughs and colds in children under 6 years old. Also, consider avoiding the use of these medicines for children younger than 12 years old. The risks to children outweigh the benefits.

Preparing for an appointment

You're likely to start by seeing your child's primary care provider or pediatrician. Here's some information to help you get ready for the appointment.

What you can do

Before your appointment, make a list of:

Questions to ask your provider may include:

Feel free to ask other questions during your appointment.

What to expect from your doctor

Your child's health care provider may ask questions, such as:

Preparing for questions will help you make the most of your time with your child's health care provider.

© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of use.