I found this article that I thought was interesting.

Allergies Double Since 1970s (http://aolsvc.news.aol.com/news/article.adp?id=20050808071709990002&ncid=NWS00010000000001)

This is good news actually. The more people that have allergies, the more research and interest this area will attract. I am amazed at how little doctors know about allergies. Even so called 'allergists'. They can treat the simple cases, but have no clue about complex ones.