Get Smart About Asthma

In healthy lungs, small muscles move air through a network of branching airways that are lined with a thin layer of mucus. When a child has asthma, these tiny tubes become inflamed, making them very sensitive to irritants, allergens, cold air, and respiratory infections. In response to a trigger, the airways produce more mucus and the muscles around them tighten -- causing a child to wheeze, cough, or become short of breath.

Although 80 percent of children with asthma are now thought to develop the disease before age 5, kids traditionally haven't been diagnosed until about ages 7 to 9. The most accurate way for a doctor to pinpoint the disease is with spirometry, a simple test in which a child blows into a tube attached to a machine that measures how forcefully she can push air out. However, doctors usually don't get reliable test results from kids under age 5. "Doctors must rely on a young child's symptoms and history to make a diagnosis," says Sheldon Spector, MD, clinical professor of medicine at the University of California, Los Angeles. If you're worried about your child's breathing, here are the key questions your pediatrician will ask.

• Does he wheeze? Although one bout of wheezing could be due to bronchitis, pneumonia, or viral bronchiolitis, recurring wheezing usually means asthma. However, a lack of wheezing doesn't rule asthma out.
• Does she have trouble keeping up with other kids? Kids with asthma typically cough or get short of breath after running around for just five or 10 minutes.
• Does he cough all the time? An asthma cough is dry, worse at night, doesn't cause a fever, and seems to hang on forever. "In some cases, asthma makes children cough so hard that they vomit," says Christopher Randolph, MD, clinical professor of pediatrics at Yale University School of Medicine.
• Does she have any allergies or eczema? These related conditions make a child more likely to develop asthma.
• Do you or your spouse have asthma? A child's risk is higher if a parent has a history of breathing difficulties or allergies.