Questions remain about the causes and recent increases in the number of children and adults with food allergies. The fact that such allergies are very common in the United States, Canada, Europe and other industrialized countries around the world, however, is undeniable. Contrary to what Times columnist Joel Stein wrote in his Jan. 9 Op-Ed column, "Nut allergies — a Yuppie invention," anaphylaxis is not brought on by the need for attention by "a parent who needs to feel special." Anaphylaxis is a serious allergic reaction that can be caused by exposure to minuscule quantities of nuts or other food allergens and may even cause death.The hives, swelling and severe breathing difficulty that people may experience during an allergic reaction are not symptoms of a "psychogenic illness," but rather an unbelievably frightening and dangerous response of the immune system to certain foods the body misinterprets as harmful. The fact is, food is the leading cause of anaphylaxis outside the hospital setting, and many children and adults die each year because they ate something they thought was safe. Once a reaction begins, no one knows how bad it will be, hence the worry and fear that is part of living with food allergies.