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What Is Bronchiolitis?

Bronchiolitis (brong-kee-oh-LYE-tiss) is an illness of the respiratory tract. It happens when tiny airways called bronchioles (BRONG-kee-olz) get infected with a virus. These airways become inflamed, then swell and fill with mucus, which can make breathing hard.

Who Gets Bronchiolitis?


  • most often affects infants and young children because their noses and small airways can easily get blocked
  • is most common during the first 2 years of life, especially in babies 3‒6 months old
  • is more common in males, premature babies, children who weren't breastfed, and those who live in crowded conditions

Kids who go to childcare or are around secondhand smoke also are at risk for bronchiolitis.

What Causes Bronchiolitis?

Bronchiolitis usually is a viral infection. Respiratory syncytial virus (RSV) causes more than half of all cases.

Other viruses that can cause bronchiolitis include:

  • rhinovirus (the common cold)
  • the flu
  • human metapneumovirus
  • adenovirus
  • coronavirus
  • parainfluenza

What Problems Can Happen?

Bronchiolitis often is a mild illness. But some babies are at risk for severe illness, including those who:

These babies need treatment for bronchiolitis in a hospital.

Kids who have had bronchiolitis might be more likely to develop asthma later in life. It's not clear whether the illness causes or triggers asthma, or whether kids who later develop asthma were more prone to bronchiolitis as infants.

What Are the Signs & Symptoms of Bronchiolitis?

The first symptoms of bronchiolitis are usually the same as those of a cold:

  • stuffy nose and congestion
  • runny nose
  • cough
  • fever

These symptoms last a day or two. They're followed by worsening of the cough and wheezing (high-pitched whistling noises when the child breathes out).

Sometimes, more severe respiratory problems happen over time. Watch for:

  • fast, shallow breathing
  • a rapid heartbeat
  • retractions — when the areas below the ribs, between the ribs, and in the neck sink in as a child inhales (breathes in)
  • flaring of the nostrils
  • irritability, with trouble sleeping and signs of fatigue (tiredness) or being very drowsy
  • vomiting after coughing
  • poor appetite or not feeding well
  • fewer wet diapers or peeing less than usual

Sometimes these problems can lead to dehydration. Less often, babies (especially preemies) may have episodes of brief pauses in their breathing (called apnea) before developing other symptoms.

In severe cases, symptoms may quickly get worse. A child with severe bronchiolitis:

  • may get very tired from the work of breathing
  • have poor air movement in and out of the lungs because the small airways are clogged
  • have blue-tinged skin (called cyanosis), especially in the lips and fingernails

Is Bronchiolitis Contagious?

The infections that cause bronchiolitis are contagious. The germs can spread in tiny drops of fluid from an infected person's nose and mouth via sneezes, coughs, or laughs. Infected droplets also can end up on things the person has touched, such as used tissues or toys.

Infants in childcare centers have a higher risk of getting an infection that may lead to bronchiolitis because they're in close contact with lots of other young children.

How Long Does Bronchiolitis Last?

Bronchiolitis usually lasts about 12 days. Kids with severe cases can cough and have wheezing for weeks.

How Is Bronchiolitis Treated?

Most cases of bronchiolitis are mild and don't need specific medical treatment. Antibiotics can't help because bronchiolitis is caused by a virus. Antibiotics work only against bacterial infections.

Doctors may give medicine to help open a child's airways.

Babies who have trouble breathing, are dehydrated, or seem very tired should be checked by a doctor. Those with serious symptoms may need to be hospitalized, watched closely, and given fluids and humidified oxygen.

Rarely, in very severe cases, doctors put the baby on a respirator to help with breathing until the baby gets better.

How Can I Help My Child?

The best treatment for most kids with bronchiolitis is time to recover and plenty of fluids. Make sure a baby gets enough to drink by offering fluids in small amounts often.

Indoor air, especially during winter, can dry out airways and make mucus stickier. You can use a cool-mist vaporizer or humidifier in your child's room to help loosen mucus in the airway and relieve cough and congestion. Be sure to clean it daily with household bleach to prevent buildup of mold or bacteria. Avoid hot-water and steam humidifiers, which can be hazardous and can cause scalding.

To clear nasal congestion, try a bulb syringe and saline (saltwater) nose drops. This can be especially helpful before feeding and sleeping. Sometimes, keeping a child in an upright position may help ease labored breathing.

You can give acetaminophen to reduce fever and make your child more comfortable. Follow the package directions about how much to give and how often to give it.

Can Bronchiolitis Be Prevented?

Washing hands well and often is the best way to prevent the spread of viruses that can cause bronchiolitis and other infections. 


  • Keep infants away from anyone who has a cold or cough.
  • Protect babies from secondhand smoke.

There's no bronchiolitis vaccine yet, but doctors can give a medicine called palivizumab to ease the severity of the disease. It's recommended only for infants at high risk for serious symptoms, such as those born very prematurely or those with chronic lung disease or heart disease. The medicine contains antibodies to respiratory syncytial virus. It's given as an injection monthly during peak RSV season.

When Should I Call the Doctor?

Call your doctor if your child:

  • is breathing quickly, especially if he or she also has retractions or wheezing
  • might be dehydrated due to vomiting or a poor appetite
  • is sleepier than usual
  • has a high fever

Get medical care right away if:

  • Your child has trouble breathing.
  • The cough, retractions, or wheezing get worse.
  • Your child's lips or fingernails look blue.