Food allergy is an abnormal response of the immune system. It typically occurs in the first several years of life. There are about eight million children in the United States that have food allergy and about four million adults.  The most common food allergies in children are milk, egg, soy, wheat, and peanut.  The eight most common food allergies overall are milk, egg, soy, wheat, and peanut, treenuts, fish and shellfish.

How is food allergy diagnosed?  It takes a combination of a really good medical history and then looking for IgE either by skin prick testing or serum test called a RAST test-- this stands for radioallergosorbent test. That is a serum test that measures allergy antibody specific for a particular food.

A positive test to either one of these indicates that a patient may be allergic to that food. It must be correlated back with the clinical condition of that child or adult when eating that food to determine the relevance of that positive test.   Positive tests with no history of reaction are often false positives and avoidance is usually not necessary.  Negative tests offer more valuable information because allergy is highly unlikely if IgE is not present (by blood or skin).

Food allergy needs to be differentiated from food intolerance.  Food intolerance is something specific to an individual. An example of food intolerance might be lactose intolerance in which there is a lack of an enzyme in the gastrointestinal tract that breaks down lactose.  When someone with lactose intolerance drinks milk products, they have excessive gas or diarrhea because of the lack of that digestion.

How can you prevent food allergy?  What we do know is that, if you have an immediate family history -- a mother, father, one of the siblings, if they have allergic disease -- then your child is at a higher risk for developing allergies. What you do while you're pregnant, we really do not understand well. The two best things you can do after delivery that may prevent any type of allergic disease -- not just food allergy -- are breastfeeding for at least four to six months exclusively and not giving your child solid foods for that same period of time. It's also important to avoid introducing the very allergenic foods until later, although the actual benefit of this is controversial and conflicting information has been reported recently.

-Hold milk until one year of age
-Hold eggs until two years of age
-Hold peanuts/tree nuts until three years of age

Food allergens do cross the placenta and into the breast milk. There is a small benefit to avoiding the very allergenic foods during pregnancy and lactation in high risk families.

To successfully manage a food allergy, your diet and lifestyle must change. These changes may seem challenging and overwhelming at first, but over time it gets easier.  Learning how to read ingredient labels correctly and accurately is the first step.  Several websites such as FAAN’s www.foodallergy.org give great advice on doing this and examples of what commonly cross contaminated foods to watch out for.  For example, most people do not know that sunflower seeds often contain traces of peanut due to the way they are manufactured.  On the other hand, most people who are allergic to peanut can eat peanut oil safely. “High risk” allergy foods include desserts, sauces, pastry-covered dishes, and fried foods.

Food allergy can be outgrown.  Milk and egg allergies tend to resolve by school age, but peanut allergy lasts forever in up to 80% of children.

If your child has been identified with a food allergy, carrying an injectable epinephrine device in case of an accidental ingestion is essential and can mean the difference between life and death.  MedicAlert bracelets are also helpful to notify healthcare professionals of important allergies if a patient is ever found unconscious or nonresponsive.