Peanuts is one of the more common allergy-causing foods.
Peanuts are not actually a true nut they are a legume (the same family as peas and lentils), but the proteins in peanuts are similar in structure to those in tree nuts so people who are allergic to peanuts can also be allergic to tree nuts, such as almonds, Brazil nuts, walnuts, hazelnuts, macadamias, pistachios, pecans, and cashews.