7 Surprising Facts About Asthma

Inhale, exhale ... inhale, exhale ... Breathing is supposed to be easy and automatic. So when your child starts wheezing, coughing fitfully, or struggling for breath, it gives even the most mellow parent high anxiety. And if your child is one of the 9 million kids in the United States who has been diagnosed with asthma, you might wish you could watch him 24/7 or be tempted to limit his activities to prevent a flare-up.

Asthma, an inflammatory disease of the airways (the tiny bronchi of the lungs), is the most common chronic condition in children. No one knows exactly why asthma is so prevalent among kids, but there are a few leading theories: Some experts blame rising levels of pollution. Others point to the fact that kids today are being raised in a more sterile environment than past generations, which leads to their immune system being more easily compromised. Another possible cause is the buildup of greenhouse gases, which are boosting production of pollen. This is significant because 70 percent of people with asthma also have allergies, according to the American Academy of Allergy, Asthma & Immunology. The current obesity epidemic may be contributing too: Kids who are overweight and have elevated levels of C-reactive protein (a marker of inflammation in the body) tend to have more severe asthma, according to a recent study from Duke Children's Hospital, in Durham, North Carolina.

But the higher rate is also because doctors are now recognizing that even very young kids can have asthma. "In the past, doctors were reluctant to make the diagnosis before age 5 or 6," says Michael Welch, M.D., clinical professor of pediatrics at the University of California, San Diego. "Now, it's more common for doctors to diagnose a preschooler, a toddler, or even a baby with asthma."

In light of how much has changed about the condition in recent years, we've gathered seven surprising key facts that will be news to many parents -- even those whose children have been diagnosed.