With spring comes birds, bees and for some, a wheeze. More than 24 million Americans have been diagnosed with asthma, but millions more may be at risk for the condition and not know it. Allergists who are members of the American College of Allergy, Asthma and Immunology (ACAAI) want people to be aware of these five little-known facts about asthma:

1. Sometimes the signs are subtle: Do you cough at night? Get winded while walking up stairs? These can be symptoms of asthma. "The lungs of a person who has asthma are inflamed all the time," said allergist Dr...