A food allergy is a medical condition in which exposure to a food triggers a harmful immune response. The immune response, called an allergic reaction, occurs because the immune system attacks proteins in the food that are normally harmless. The proteins that trigger the reaction are called allergens. Food allergies can be life-threatening and are a serious and growing public health problem. People visit the emergency room about 200,000 times each year because of food allergies. Almost 10,000 people stay in the hospital each year because of food allergies.
Children have food allergies more often than adults. Eight foods cause most food allergy reactions. They are milk, soy, eggs, wheat, peanut, tree nuts, fish and shellfish. In 2014, 4 million children in the US had a diagnosis of food allergies. About 38.7% of food allergic children have a history of severe reactions. In children with food allergies, 30% are allergic to multiple foods.
The Centers for Disease Control & Prevention reports that the prevalence of food allergy in children increased by 50 percent between 1997 and 2011. Between 1997 and 2008, the prevalence of peanut or tree nut allergy appears to have more than tripled in U.S. children.