Although the U.S. asthma death rate grew an extraordinary 118 percent between 1975 and 1995, in Great Britain, where the asthma rate also is skyrocketing, deaths from the disease have been cut in half in recent years. Americans worry about steroids stunting growth, but they are necessary, Holgate said. The high U.S. death rate is just one of asthma's scientific puzzles. Although it's classified as a single disease, many experts now think it's a host of similar ailments. Yet they can't figure out how to differentiate among them.
Dust mites, mold, pollution and cockroach parts often trigger asthma attacks.
Yet one leading medical theory suggests the disease might be caused by the reaction of young immune systems, developed under modern antiseptic lifestyles, to triggers such as dirt. This hypothesis says modern antibiotics and hygienic living mean there are fewer bugs, parasites and diseases for babies to be exposed to before and just after birth. Instead of fighting off diseases, the immune system hasn't much to do. They're going to get in trouble because they don't have anything to pick on. But this doesn't explain what's happening in America's inner cities and why only certain people with allergies get asthma.