Why Are Allergies On The Rise?

(From The Washington Post)
  
Experts estimate that many allergies and immune system diseases have doubled, tripled, or quadrupled in the last few decades.

But why?

It may be that modern, clean living leaves the immune system untested and more likely to overreact to allergens.

As one researcher put it, "Our immune systems are much less busy, and so have much more strong responses to much weaker stimuli, triggering allergies and autoimmune diseases."

Some question the theory, but others are testing giving small amounts of allergenic foods, for example, to try to train the immune systems of people with allergies.

Others are using parasitic worms to improve autoimmune diseases such as CROHN'S DISEASE.