BOSTON -- Food allergies are a growing problem in the United States. Fatal food allergies are most common in teens. News Center 5's Liz Brunner reported Thursday on how to protect kids from making a fatal mistake.

Seth Greenwald, of Sharon, suffers from severe food allergies.

VIDEO: Teens With Food Allergies Take Risks "Nuts, peanuts, fish, sesame. Basically every food except for apples and strawberries and blueberries," Greenwald said.

For Greenwald, eating the wrong food can be terrifying. For example, one small bite from a peanut butter sandwich could leave him gasping for breath.

"My throat closes up," he said.

Seth is one of three million school-aged children suffering. According to the Food Allergy & Anaphylaxis Network, peanut allergies in particular have doubled in the past 10 years. Scientists don't fully understand why, but one thing is certain: the highest risk of fatal food reactions happens in teens.

"Sixty-nine percent of the fatalities were in the age group of 13 to 20 years," said Dr. Michael Young, a pediatric allergist with Children's Hospital Boston.

Young wrote "The Peanut Allergy Answer Book." He said risky teen behavior can contribute to fatal food reactions.

"There's more risk taking behavior because of peer pressures of being an adolescent," he said.

In a recent survey conducted by researchers at Mount Sinai Medical Center in New York and the Food Allergy & Anaphylaxis Network teens admitted not carrying life-saving medications with them, or eating foods on purpose, because of pressure.

"By the time a child has reached his teenage years, they may have forgotten that they'd actually had a life-threatening rash when they were a toddler," said Young.

Young said when teens are on their own, they no longer rely on their parents to manage their allergies.

"The greatest fear of parents was death. The greatest fear from the teenage was social isolation," Young said.

The Food Allergy & Anaphylaxis Network says the key to preventing fatal reactions is to educate teens and their friends.

Greenwald is confident he is prepared.

"I know what to do. I know how to handle it," he said.