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Pronounced: Bronk-ee-oh-LIE-tus

En Español (Spanish Version)


Bronchiolitis is a childhood disease that affects the lungs. It occurs when a virus enters the breathing system and causes the tiny airways in the lungs to become swollen. As a result, a thick fluid called mucus collects in the airways and makes it hard for air to flow freely in the lungs. Usually, the infection goes away after 7-10 days. Some children show very mild symptoms, but in others, the disease can be severe. Older children are less at risk, and if they get bronchiolitis, they don’t get as sick as younger children.



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Bronchiolitis is caused by several kinds of viruses. It easily spreads from person to person in the same way a common cold does. This often happens when droplets of moisture that are coughed or sneezed into the air by an infected person are then breathed in by a noninfected person.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Bronchiolitis can affect anyone, but it most often strikes:

  • Children under the age of two, especially between 3-6 months old
  • During the winter months
  • Adults most at risk are those who are:
    • Immunocompromised
    • Exposed to toxic fumes
  • Children most at risk are those who:
    • Were never breastfed
    • Were born prematurely
    • Are exposed to tobacco smoke
    • Are often in groups of children (as in day care) or live in crowded conditions


Symptoms of bronchiolitis occur in two stages.

During the first 2-3 days the child will probably have a:

  • Runny or stuffy nose
  • Slight fever

During the next 2-3 days, the symptoms increase to include:

  • Cough (dry)
  • Fever
  • Sneezing
  • Rash
  • Red eyes
  • Fast rate of breathing
  • Difficulty breathing
  • Wheezing (making a whistling noise during breathing)
  • Bluish color in the skin, especially around the lips or nails
  • Poor feeding
  • Restlessness


To diagnose bronchiolitis, the doctor may do one or more of the following:

  • Listen to the child’s lungs to check for abnormal breathing, such as wheezing.
  • In severe cases, take a chest x-ray to check for swelling in the airways and signs of pneumonia .
  • Collect a sample of mucus from nose or throat to test for the virus that may be causing the infection.
  • Do a blood test to determine the level of oxygen in the blood.
  • Collect a blood test for complete blood count.


There is no medication to cure viral infections. Bronchiolitis usually clears on its own after a week or ten days. There are several ways to make the child more comfortable while he or she is experiencing symptoms:

  • Have the child drink clear liquids.
  • Use a vaporizer in the bedroom.
  • When the child is coughing or having difficulty breathing, steam the bathroom using hot water from the shower, and sit in there with him or her.
  • Advise smoking parents to not smoke in front of child.
  • Use acetaminophen (eg, Children’s or Infant’s Tylenol) if a fever is present.

In severe cases, medical treatment may be necessary. The doctor will check for dehydration (excessive loss of body water) and pneumonia, and make sure the child is getting enough oxygen. Medications (eg, antibiotics) may be given as necessary. Call the doctor if the child:

  • Is vomiting and can’t keep liquids down
  • Is breathing very fast (more than 40 breaths in one minute)
  • Has bluish skin, especially around the lips or on the fingertips
  • Has to sit up to breathe
  • Was born prematurely or has a history of heart disease
  • Appears dehydrated

Sometimes doctors prescribe corticosteroids (strong anti-inflammatory medications) to help reduce the swelling and mucus in the airways. Although this is common practice, evidence regarding its benefits has been limited. In a recent study, researchers divided 600 infants visiting the emergency room with their first episode of sudden moderate-to-severe bronchiolitis into two groups. One group received a single dose of an oral corticosteroid (dexamethasone) and the other group received a placebo. The researchers found no significant difference between the two groups including the rate of hospitalization, breathing status, or later problems. *


Since bronchiolitis spreads easily from one person to another, children should be kept home until they are well to prevent giving the infection to others. There is no vaccine to prevent bronchiolitis. However, there is a medication to lessen the risk of infection by respiratory syncytial virus (RSV) , a virus which causes more than half of all cases of bronchiolitis. This medication is usually given to high-risk babies.

Proper handwashing habits can help to prevent the spread of bronchiolitis, especially before touching a baby or after being in contact with an infected one.


American Academy of Family Physicians

National Library of Medicine and the National Institutes of Health


BC Children’s Hospital

The Canadian Lung Association

The Canadian Paediatric Society


Beers MH, Fletcher AJ, Jones TV, et al, eds. The Merck Manual of Medical Information . 2nd ed. Whitehouse Station, NJ: Merck Research Laboratories; 2003.

Bronchiolitis. Medline Plus website. Available at: . Accessed August 4, 2005.

Bronchiolitis and your child. American Academy of Family Physicians website. Available at: . Accessed August 4, 2005.

Gadomski AM, Bhasale aL: Bronchodilators for bronchiolitis. Cochrane Database Syst Rev 2006 :CD001266.

Smyth RL, Openshaw PJ. Bronchiolitis. Lancet. 2006;368:312-322.

Steiner RWP. Treating acute bronchiolitis associated with RSV. Am Fam Physician. 2004;69:325-330.

Updated Treatment section on 8/10/2007 according to the following study, as cited by DynaMed's Systematic Literature Surveillance : Corneli HM, Zorc JJ, Majahan P, et al. A multicenter, randomized, controlled trial of dexamethasone for bronchiolitis. N Engl J Med. 2007;357:331-339.

Last reviewed January 2008 by David Juan, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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