June 20, 2011 -- The largest study ever to track childhood food allergies in the U.S. shows that they may be more common and more dangerous than previously recognized.

The study, a detailed survey of families with at least one child younger than 18, shows that 8% of kids under age 18 are allergic to at least one food. Surveys for about 38, 000 children were completed.

Previous studies, including a government survey published in 2009, had pegged that number at around 4%.

Allergies to peanuts were the most commonly reported, affecting 2% of kids. Milk and shellfish allergies ranked second and third. Tree nuts, egg, fin fish, strawberry, wheat, and soy rounded out the top nine food triggers.

"This study shows that there's a very high, and higher than we thought, prevalence of food allergy in the U.S." says Susan Schuval, MD, pediatric allergist at Cohen Children's Medical Center in New Hyde Park, N.Y., who was not involved in the study.

"We see this in our clinic," Schuval says, "tons and tons of food allergies."