Environmental Triggers

Allergic asthma affects about 3 million children and 7 million adults in the United States at a cost estimated at $6.2 billion a year.

Some theorize that a decline in serious illnesses may be a factor in the increase in allergic asthma, with an under-utilized immune system overreacting to lesser threats or irritants, inappropriately producing antibody molecules that result in a release of histamine and other inflammatory substances in the lungs. Other researchers implicate the increased time youngsters spend indoors — and their resulting exposure to carpeting and other allergen-catchers that people in developed nations surround themselves with.

What is known is that dust mites, cockroaches, molds, pollens and domesticated animals produce some of the substances, called allergens, known to trigger asthma attacks. A study is now underway to determine the roles of other key environmental agents in asthma, both in bringing on respiratory crisis and initiating the illness in the first place. The research is being supported jointly by scientists at the National Institute of Environmental Health Sciences and the National Institute of Allergy and Infectious Diseases, two of the National Institutes of Health.