Understanding Food Allergies in Kids

Every year, thousands of parents learn of their children's food allergies following a reaction that can affect many body systems, including the respiratory system, the gastrointestinal tract, skin or cardiovascular system. About 2 million school age children have a food allergy, and one child in 20 under age 3 has a food allergy.

Food allergies develop when the immune system misinterprets a food as harmful and develops an immune response against the food. Before experiencing an allergic reaction to a food, a child must have been exposed to the food at least once before, which can occur through breast milk. If a child develops allergy antibodies (called IgE) to a food protein, reexposure to that food may be accompanied by a release of histamine and other chemicals. These chemicals produce the allergic symptoms.

Allergies of any kind are often inherited. A child with two allergic parents is more likely to develop food allergies than someone with one allergic parent, even if the parent’s allergy is to something other than food, such as pollen.

Leonard Bacharier, M.D., assistant professor of pediatrics at Washington University School of Medicine in St. Louis and an attending physician in pediatric allergy and pulmonary medicine at St. Louis Children's Hospital, said some evidence shows that starting babies too early – before age 4-6 months – on solid food increases the risk of food allergies.

“There are many different recommendations about what age to allow certain foods, making it confusing and frustrating to many parents,” he says. “However, general guidelines suggest delaying the introduction of the common and most dangerous offenders as long as possible – at least until age 2. In addition, exclusive breastfeeding for the first four to six months of life appears to decrease the likelihood of subsequent allergy.”

Specifically, the American Academy of Pediatrics offers the following guidelines of when to introduce certain foods: after age 1 – cow’s milk; after age 2 – eggs; and after age 3 – fish, shellfish, peanuts and tree nuts (such as almonds, cashews and walnuts).

The eight foods that cause 90 percent of food allergies include:

• Peanuts
• Shellfish
• Fish
• Tree nuts (walnuts, pecans, pistachios, Brazil nuts, cashews, almonds and coconut)
• Eggs
• Milk
• Soy
• Wheat

Symptoms of an allergic reaction can range from mild to severe, and may include one or more of the following:

• Hives (a red intensely itchy rash)
• Eczema
• Tingling sensation in the mouth
• Swelling of the tongue and/or throat
• Difficulty breathing, coughing and/or wheezing
• Nausea and vomiting
• Abdominal cramps• Diarrhea• Drop in blood pressure• Loss of consciousness• Death• Anaphylaxis is a combination of several of these symptoms and is a life threatening medical emergency.