"Sometimes treatment can be part of the problem," she said.
Nowadays, medications such as long-acting beta agonists (LABAS) and corticosteroids can prevent flare-ups. Drugs like albuterol, and oral and intravenous corticosteroids, are taken for sudden attacks. Anti-allergy medications are also used to prevent bouts of the disease over time.
But Dahl also said she noticed that many of her asthma and allergy patients had other inflammatory diseases such as arthritis and irritable bowel syndrome. However, "it is hard to know if one is causing the other, or if they are just found together," by coincidence, she said.
Asthma can prove deadly on its own, of course. According to the American Academy of Allergy, Asthma and Immunology, close to 3,400 deaths from asthma occurred in 2005.
"It's a wildcard," said Appleyard, noting that asthma-related deaths occur equally among those who have mild, moderate or severe cases.
Find out more about asthma at the U.S. National Heart, Lung and Blood Institute.
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