Can we alter the course of allergic disease?

It becomes obvious from this outline that the increase in each form of allergic disease results from very different causes. In no case were the consequences in relation to allergic disease predicted, and it is difficult to believe that any of these changes could have been stopped if we had known what was going to happen. Basically, what we are watching is the inexorable progress of modern civilization with all its intended and unintended consequences. What we would like to emphasize is that the basic changes in hygiene, clean water, complete separation of fecal matter from food production, and helminth eradication were complete before most of the major rises in allergic disease. Thus, all the diseases we discuss occurred “post-hygiene.” There is one major change that arguably has decreased the severity of 2 allergic diseases, that is modern air conditioning and the closing of houses so that air exchange rates are as low as 0.6 air changes per hour. This means that only minimal quantities of pollen can enter the houses but also that houses become drier and less hospitable to mites. In keeping with these changes in houses and apartments, both hay fever and asthma have become less severe since 2000. Needless to say, these effects were never advertised as a reason for the change.