Anne Lent, MD Pediatrics

April 28, 2009

We’ve all heard the scary tales of children having severe allergic reactions to food. Yet what is a true allergy? Should you withhold certain foods from your child to avoid such severe reactions? Will my child ever outgrow the allergy? Is there anything that I can do to prevent my child from developing a food allergy? What are the signs of a food allergy? To answer these questions, it is important to first understand the difference between a food “allergy” and a food “intolerance”.

An allergy is an immune response to a particular substance (ie., to a pollen, an animal, and, in this case, to a food). Symptoms of “allergic” reactions to food range from mild to severe and include shortness of breath, swelling of the lips, tongue and throat, and skin manifestations such as hives. Occasionally an allergic reaction can reek havic on the gastrointestinal tract causing abdominal pain, diarrhea, or nausea. True “allergic” reactions occur quickly, generally within 30 minutes of the ingestion.

On the other hand, a food intolerance is not a true immune response.

An intolerance occurs when a particular food irritates or is unable to be properly digested or “broken down” by the body. Signs of food intolerence are generally limited to the gastrointestinal tract (nausea, vomitting, and abdominal pain) yet may occasionally cause headaches, anxiousness, irritability, and even skin rashes. Intolerance to various foods may occur intermittently, whereas true allergic reactions occur consistently after a partcular food is ingested.

True allergic reactions to food are not as prevalent as many parents fear. A study presented in March at the annual meeting of the American Academy of Allergy, Asthma & Immunology, showed that only 2.5% of children have a clinical food allergy, with allergies to peanuts and shrimp being the most common. With the exception of peanuts and shellfish, most children outgrow food allergies by the age of 5.

Our understanding of food allergies is evolving on a daily basis, creating significant controversy surrounding potential causes and methods of prevention. It is likely that there are many causative factors including genetics and environmental exposures that play into whether a child does or does not develop an allergy. Unfortunately, such confusion has complicated recommendations doctors make to parents. A rule of thumb is to avoid introduction of solid foods until 6 months and to recognize the signs and symptoms of allergic reactions.

Seek immediate medical attention if your child has difficulty breathing, swelling of the lips, tongue or eyes, hives (and other rashes), and gastrointestinal symptoms after eating a particular food.