Disease Database Drug Database Alt. In preschool once, a classmate's peanut butter-smeared hands set off an emergency, even though Aly was sitting at another table.
Nobody is sure why peanuts, a legume more related to soy than tree nuts, are so allergenic.
Experts suspect the allergy is on the rise. Partly that's because children today eat peanut products at earlier ages, and early exposure increases the risk that someone who is genetically susceptible to the allergy will actually develop it, says Dr. Wesley Burks of Arkansas Children's Hospital. Half of all allergy sufferers accidentally eat peanuts at least once every two years. Even foods not supposed to contain peanuts really can, such as when manufacturers use the same machine to mix up, say, peanut butter ice cream that they later use to mix plain chocolate. IgE, or immunoglobulin-E, plays a major role in asthma and numerous allergies, stimulating immune cells to overreact when exposed to certain allergens.