Definition of Bronchiolitis

RSV virus
RSV virus. Photo © ADAM


Bronchiolitis is inflammation of the smaller airways of the lungs, called bronchioles, which causes wheezing as air moves in and out of the lungs. Bronchiolitis usually affects children under 2 years of age during the winter months.

Bronchiolitis is generally caused by one of the following viruses:

  • Respiratory syncytial virus (RSV)
  • Adenovirus
  • Influenza
  • Parainfluenza


Are Bronchiolitis and Asthma the Same Thing?


Not all that wheezes is asthma, but wheezing should almost always be checked out. If your child has never wheezed and you hear wheezing, you should call your doctor and ask what to do. Some of the viruses listed above can cause your child to wheeze for a couple of weeks and they can lead to what many doctors refer to in adults as "post viral syndrome."

Does Bronchiolitis lead To Asthma?

The respiratory syncytial virus or RSV can lead to symptoms of asthma such as wheezing, chest tightness, shortness of breath and cough. About 4 in 10 children that require hospitalization for bronchiolitis may end up being diagnosed with asthma later in life. However, most kids do not go on to develop the diagnosis.

Will I Or My Child Wheeze Again? Do I Have Asthma?

The short answer is maybe. About 1 in 3 children who wheeze in the first few years of life will still be wheezing at age 6. The more times you wheeze in a year or requiring steroids are two of the big predictors as well as having a parent with asthma or atopic disease.

What Tests Might My Doctor Order They Suspect Bronchiolitis?

In young children your doctor is not able to perform tests such as FEV1. The most common test your doctor will order will be a chest x-ray. This will help you doctor tell if an infection may be causing the wheezing or if there is some sort of structural problem that is leading to the wheezing.

Your doctor may also order blood tests if they are suspicious for other causes of wheezing.


1. Castro-Rodriguez J. The Asthma Predictive Index: early diagnosis of asthma.. Curr Opin Allergy Clin Immunol. 2011 Jun;11(3):157–61. Accessed on October 18, 2015.

2. National Heart, Lung, and Blood Institute. Accessed on October 18, 2015. Expert Panel Report 3 (EPR3): Guidelines for the Diagnosis and Management of Asthma

3. Medline Plus. Accessed on October 18, 2015. Respiratory syncytial virus (RSV)



Continue Reading