Before my first child was born, I read every book under the sun about the dangers she might face by just simply being a child. I worried about eggs, honey, peanuts and, of course, vaccines. For the first year, at least, I lived in constant fear of what my baby might be allergic to.

Were my concerns legitimate? Maybe so. I need two hands to count the number of personal friends whose asthmatic children have needed nebulizers on more than one occasion because even what seems like a common cold runs out of control.

Its terrifying.

My mother, a nurse practitioner, shakes her head when I share these stories with her. It wasnt like that when we were kids, she tells me. So why does it seem like every kid you meet nowadays is allergic to something? Thats the question we asked ourselves when we embarked on this months special report, Why Are Allergies on the Rise?

Shocking Allergy Facts More than half of all Americans (54%) test positive to at least one of the top 10 allergens. In North America in the 1930s and 1940s, only about 3% of people (and up to 10% in ragweed-infested areas) were estimated to have hay fever (i.e., allergic rhinitis). During the past decades, however, the prevalence of allergic rhinitis has continued to increase, from 10% of the population in 1970 to 30% of adults and 40% of children in 2000. In the United States, food allergy is the leading cause of anaphylaxis outside the hospital setting. In fact, the number of children allergic to peanuts doubled between 1997 and 2002.

In his search to uncover a cause for the skyrocketing rise in allergic disease, Senior Editor John Murphy takes a closer look at the history of allergies in the United States and the latest theories on whats causing them.

Among the hypotheses: increased pollen production, which goes hand-in-hand with increased allergy. Whats more, carbon dioxide in the atmosphere is predicted to double by the end of this century. More carbon dioxide equates to more pollen production. And, such an increase would lead to an estimated 61% more pollen from ragweed, according to researchers at Harvard Medical School.1

While many researchers point to our dirty environment as the culprit in the allergy explosion, others make a case that the earth is not too dirty; its too cleanthanks, in part, to our over-zealous desire to sanitize the germs out of our kids lives with the latest and greatest in antibacterial germ-fighting potions.

Of course, none of the proposed theories are without flaws. All of them raise just as many questions as they answer.

Until there are some definitive guidelines on how to protect our kids and ourselves, we are left with the symptoms and new conditionse.g., urban eye allergy syndrome. This months report also includes a case report on this somewhat newly-defined condition, which is caused by pollution and has a presentation akin to an allergy-like conjunctivitis.

As always, I hope you find this months issue clinically informative as well as helpful when addressing your patients concerns about allergic disease.

1. Wayne P, Foster S, Connolly J, et al. Production of allergenic pollen by ragweed (Ambrosia artemisiifolia L.) is increased in CO2-enriched atmospheres. Ann Allergy Asthma Immunol 2002 Mar;88(3):279-82.