Asthma May Result from Wheezing During a Cold
Young children who wheeze when they have rhinovirus infection - the most common cause of colds - are at much greater risk of developing asthma later during childhood, says a study in the American Journal of Respiratory and Critical Care Medicine.
Previous research had shown that infants who experience viral respiratory illnesses with wheezing are more likely to develop asthma.
But, until now, it has not been clear whether all types of respiratory viruses that produce wheezing are associated with this increased risk.
The new study found that the rhinovirus-produced wheezing should concern parents the most.
"We have found that rhinovirus, the most common cause of colds, contributes a disproportionate amount toward future asthma development in comparison to other viruses that also cause childhood wheezing," says Dr. Robert F. Lemanske, Jr., at the University of Wisconsin, lead investigator of the study.
The researchers followed a group of nearly 300 newborns at increased risk for asthma from one or both parents having allergies or asthma.
The children were evaluated for the presence of respiratory viruses and for the development of asthma until they were six years old.
At age six, 28 percent of the children had asthma, with a disproportionate amount of them having wheezed from rhinovirus.
The children who wheezed from rhinovirus during the first year of life were nearly three times as likely to have asthma when they were six years old, compared with children who wheezed from respiratory syncytial virus (RSV, another common respiratory ailment) and did not have increased asthma risk.
The older the children were when the rhinovirus-associated wheezing occurred, the greater the effect, the study found.
Children who wheezed with rhinovirus at age two were more than six times as likely to have asthma; at age three, the risk was more than 30-fold.
The findings provide important information about the type of wheezing-inducing virus that is associated with an increased risk of asthma.
However, the researchers cannot say whether rhinovirus causes asthma to develop or simply reveals children who will develop the disease.
"In genetically susceptible children, [rhinovirus] wheezing illnesses could cause airway damage as well as subsequent asthma (virus-related factors)," says Dr. Daniel L. Jackson, of the University of Wisconsin.
But Dr. Jackson points out that additional research is needed to determine whether rhinovirus leads to asthma development.
Always consult your child's physician for more information.
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Asthma is a chronic, inflammatory disease in which the airways become sensitive to allergens (any substance that triggers an allergic reaction).
Several things happen to the airways when a child is exposed to certain triggers: the lining of the airways become swollen and inflamed; the muscles that surround the airways tighten; and the production of mucus is increased, leading to mucus plugs.
All of these factors will cause the airways to narrow - thus, making it difficult for air to go in and out of your child's lungs, causing the symptoms of asthma.
According to the American Lung Association, the Centers for Disease Control and Prevention (CDC), and the National Institute of Allergy and Infectious Diseases (NIAID):
- Approximately 22.2 million people in the US have been diagnosed with asthma, with at least 6.5 million of them children under the age of 18.
- Asthma is the leading, serious, chronic illness among children in the US.
- Asthma accounts for 14 million absences from school each year.
- Asthma is the third-ranking cause of childhood hospitalizations under the age of 15.
The exact cause of asthma is not completely known. It is believed to be partially inherited, but it also involves many other environmental, infectious, and chemical factors.
After a child is exposed to a certain trigger, the body releases histamine and other agents that can cause inflammation in your child's airways.
The body also releases other factors that can cause the muscles of the airways to tighten, or become smaller. There is also an increase in mucus production that may clog the airways.
The following are the most common symptoms of asthma:
- coughing (either constant or intermittently)
- wheezing (this is a whistling sound that may be heard while your child is breathing)
- trouble breathing or shortness of breath while your child is playing or exercising
- chest tightness (your child may say his/her chest hurts or does not feel good)
- fatigue
- nighttime cough
- noisy breathing
Always consult your child's physician for more information.
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