By the time a toddler reaches school age, food allergies have usually presented themselves. However, it can be important to remember that allergic reactions to foods served in a school setting are possible.
According to the American Academy of Allergy, Asthma and Immunology (AAAAI), about 25 percent of reactions in school-age children occurred at school, either in cafeterias, playgrounds or classrooms.
From: toddlerstoday.com