An estimated 12-million Americans have food allergies, which send about 30,000 to emergency rooms each year. At least 100 die a year.
And food allergies are on the rise.
"For reasons that we don't understand, the prevalence of food allergies has doubled in the last 15 years," says Wesley Burks, chief of allergy and immunology at Duke University Medical Center.
Among the theories for the increase are changes in the way food is processed and the age when solid food is fed to infants. Some experts also contend that our obsession with cleanliness overprotects the immune system, which then reacts too aggressively when confronted with perceived foreign invaders, such as peanuts.
During a food allergy attack, the immune system overreacts to specific food proteins and manufactures too much immunoglobulin E. That sets in motion a series of reactions that can produce anything from itchy hives to a life-threatening anaphylactic attack.
Severity of the reaction varies with genetic makeup and how much of the food has been eaten. Some of the most severe reactions are to peanuts and cashews.
Food allergies afflict about 4 percent of adults and 8 percent of children age 2 and younger. The good news: Many children outgrow their allergies.
Doctors diagnose food allergies through blood and skin tests, coupled with a physical exam and a history of food-related problems.
Robert A. Wood, a doctor at Johns Hopkins University, wrote in 2003 that milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat account for about 90 percent of the food allergy reactions in the United States.
The most common allergy in the United States is to milk proteins. (This is different from lactose intolerance, which affects 50-million Americans.)
The only sure way to manage food allergies is to avoid foods that cause the reactions and to be prepared for the problems caused by accidental exposure.
Since January 2006, the Food and Drug Administration has required food manufacturers not only to list leading ingredients that could cause allergies, but also to indicate if products have been produced with equipment that could contain residues of allergy-causing foods.
Duke's Burks predicts that some treatment could be available within five years. In the meantime, here's what experts recommend:
- Always read food labels. Formulations of products can change.
"Don't assume that because it was safe last month, that it will be safe this month," says Anne Munoz-Furlong, founder and head of the Food Allergy and Anaphylaxis Network.
- Look beyond traditional food products. Pet food and bath products can contain food allergens.
Where to turn
- Food Allergy and Anaphylaxis Network: toll-free 1-800-929-4040; e-mail firstname.lastname@example.org.
- National Institute of Allergy and Infectious Diseases, which publishes a 35-page booklet on food allergies: (301) 496-5717.