Allercy and Asthma Health
The Official Publication of AAN - MA

Our Doctor Diagnosed RSV Bronchiolitis in Our Child — Can It Cause Asthma?


By Claire Aloan, MS, RRT-NPS, FAARC

What exactly is bronchiolitis? Bronchiolitis is a very common viral infection that usually occurs in infants under 12 months of age. Like many viral infections, it starts with upper airway symptoms such as nasal congestion and a runny nose, along with a low-grade fever.

After two to four days, bronchiolitis progresses to the lower airways (bronchioles), causing symptoms such as cough, wheezing, rapid breathing rate, and signs of difficulty breathing, very similar to symptoms seen with asthma.

Most physicians agree bronchiolitis can be defined as “the first time wheezing occurs in an infant under 12 months of age,” although some say 24 months. There is some controversy about this definition, as it is often difficult to know if it’s really the first episode of wheezing.

What causes bronchiolitis? The most common virus causing bronchiolitis is the respiratory syncytial virus or RSV, so we often hear the term “RSV bronchiolitis.” Other viruses can also cause bronchiolitis. While approximately 20% of children under the age of one year will require medical attention due to infection with RSV, only 2-3% will have a serious enough infection to require hospitalization.

What is the relationship between bronchiolitis and asthma? Many researchers have looked at the relationship between bronchiolitis and the development of asthma in children. Because there are so many factors related to the development of asthma, including things like family history and exposure to irritating substances in the atmosphere, it is difficult to determine if there is a simple cause-and-effect relationship between bronchiolitis and asthma.

What is known, though, is that infants who have severe bronchiolitis requiring hospitalization do have a higher rate of developing asthma. This risk is increased if there is a family history of asthma. Work is underway to learn more about this relationship and how it works. A better understanding may help us know more about how and why asthma develops, and perhaps help us learn how to prevent it!

So what can you do to help protect your child? Currently, there is no vaccine against RSV. For infants at very high risk from infection, such as those who were born very prematurely and some infants with heart defects and chronic lung problems, a preventive drug may help make symptoms less severe. But this drug has not been shown to be useful in other infants.

The main thing you can do as a parent is to protect your child from being infected with the virus. This means decreasing exposure to tobacco smoke, washing your hands frequently with soap and water, cleaning potentially contaminated surfaces like doorknobs, avoiding touching your nose or mouth, and avoiding contact with those with respiratory illness: all the things we know help to prevent the spread of viruses, including RSV.

Claire Aloan is a member of the American Association for Respiratory Care from New York, where she serves as an associate professor and chair of the department of respiratory therapy education at SUNY Upstate Medical University in Syracuse.

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