Overview

Bronchiolitis is a common lung infection in young children and infants. It causes inflammation and congestion in the small airways (bronchioles) of the lung. Bronchiolitis is almost always caused by a virus. Typically, the peak time for bronchiolitis is during the winter months.

Bronchiolitis starts out with symptoms similar to those of a common cold but then progresses to coughing, wheezing and sometimes difficulty breathing. Symptoms of bronchiolitis can last for several days to weeks, even a month.

Most children get better with care at home. A very small percentage of children require hospitalization.

Symptoms

For the first few days, the signs and symptoms of bronchiolitis are similar to those of a cold:

  • Runny nose
  • Stuffy nose
  • Cough
  • Slight fever (not always present)

After this, there may be a week or more of difficulty breathing or a whistling noise when the child breathes out (wheezing).

Many infants will also have an ear infection (otitis media).

When to see a doctor

If it's difficult to get your child to eat or drink and his or her breathing becomes more rapid or labored, call your child's doctor. This is especially important if your child is younger than 12 weeks old or has other risk factors for bronchiolitis — including premature birth or a heart or lung condition.

The following signs and symptoms are reasons to seek prompt medical attention:

  • Vomiting
  • Audible wheezing sounds
  • Breathing very fast — more than 60 breaths a minute (tachypnea)  — and shallowly
  • Labored breathing — the  ribs seem to suck inward when infant inhales
  • Sluggish or lethargic appearance
  • Refusal to drink enough, or breathing too fast to eat or drink
  • Skin turning blue, especially the lips and fingernails (cyanosis)

Causes

Bronchiolitis occurs when a virus infects the bronchioles, which are the smallest airways in your lungs. The infection makes the bronchioles swell and become inflamed. Mucus collects in these airways, which makes it difficult for air to flow freely in and out of the lungs.

Most cases of bronchiolitis are caused by the respiratory syncytial virus (RSV). RSV is a common virus that infects just about every child by the age of 2. Outbreaks of the RSV infection occur every winter. Bronchiolitis can also be caused by other viruses, including those that cause the flu or the common cold. Infants can be reinfected with RSV because at least two strains exist.

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

Risk factors

Infants younger than 3 months of age are at greatest risk of getting bronchiolitis because their lungs and immune systems aren't yet fully developed.

Other factors that are associated with an increased risk of bronchiolitis in infants, or more severe illness due to bronchiolitis, include:

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

Complications

Complications of severe bronchiolitis may include:

  • Blue lips or skin (cyanosis). Cyanosis is caused by lack of oxygen.
  • Pauses in breathing (apnea). Apnea is most likely to occur in premature infants and in infants within the first two months of life.
  • Dehydration.
  • Low oxygen levels and respiratory failure.

If these occur, your child may need hospitalization. Severe respiratory failure may require that a tube be inserted into the trachea to help the child's breathing until the infection has run its course.

If your baby was born prematurely, has a heart or lung condition, or has a compromised immune system, watch closely for beginning signs of bronchiolitis. The infection can quickly become severe. In such cases, your child will usually need hospitalization.

Prevention

Because the viruses that cause bronchiolitis spread from person to person, one of the best ways to prevent it is to wash your hands frequently — especially before touching your baby when you have a cold or other respiratory illness. Wearing a face mask at this time is appropriate.

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

Other commonsense ways to help curb infection include:

  • Limit 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.
  • Clean and disinfect surfaces. Clean and disinfect surfaces and objects that people frequently touch, such as toys and doorknobs. This is especially important if a family member is sick.
  • Cover coughs and sneezes. Cover your mouth and nose with a tissue. Then throw away the tissue and wash your hands or use alcohol hand sanitizer.
  • Use your own drinking glass. Don't share glasses with others, especially if someone in your family is ill.
  • Wash hands often. Frequently wash your own hands and those of your child. Keep an alcohol-based hand sanitizer handy for yourself and your child when you're away from home.
  • Breast-feed. Respiratory infections are significantly less common in breast-fed babies.

Vaccines and medications

There are no vaccines for the most common causes of bronchiolitis (RSV and rhinovirus). However, an annual flu shot is recommended for everyone older than 6 months.

Infants at high risk of the RSV infection, such as those born very prematurely or with a heart-lung condition or a depressed immune system, may be given the medication palivizumab (Synagis) to decrease the likelihood of RSV infections.