Dr. John "Drew" Bird, a pediatrician at the University of Texas Southwestern Medical Center in Dallas who specializes in food allergies, said peanut butter-and-jelly sandwiches -- along with other lunchbox staples -- could turn life-threatening for children with food allergies.

Bird, who also is clinical director of the Food Allergy Center at Children's Medical Center Dallas, said in an allergic child just smelling or touching a food can trigger a reaction.

"The most serious and potentially life-threatening reactions are most likely to occur if the allergen has been ingested," Bird said in a statement. "Physical contact with the allergen most often leads to a hive."

Families must be vigilant whenever their allergic child is around food making eating in restaurants, at school, or at a friend's house more difficult to ensure the food the child is eating is not contaminated with an allergen, Bird said.

Bird advised because of the difficulty in predicting when and where a reaction will occur, all individuals with food allergies or their caregivers should carry two doses of auto-injectable epinephrine with them at all times.