The Nuts and Bolts of Food Allergy

Posted on: 01/29/2009

Anatole Kleiner, MD

 

Sitting down for a nice dinner with family and friends can be one of life’s great pleasures.  However, for individuals with food allergy, meals can be a time of uncertainty and distress.  Fortunately, a number of simple measures can be taken to minimize the apprehension associated with eating and to make mealtimes safe and enjoyable.

What is food allergy?

Our immune system exists to protect us from harmful foreign substances.  For example, when the cells of the immune system recognize a bacteria in the blood, the immune system will then "attack" and "destroy" the bacteria to prevent further spread of infection in the body.  In the case of food allergy, the immune system is not working correctly, and mistakenly attacks benign substances such as foods. When it comes into contact with the food in question, the immune system releases histamine and other chemicals, which cause the symptoms of food allergy.

How common is food allergy?

Food allergy affects between 2% and 3.5% of adults and from 6% to 8% of all children.  Food allergy is more common in individuals with atopic dermatitis, latex allergy, and certain pollen allergies.  An interesting fact is that while almost any food can be associated with food allergy, only a small group of foods is responsible for over 90% of the cases of food allergy.  These foods are peanuts, tree nuts, soy, shellfish, fish, cow’s milk, egg, and wheat.  The most severe allergic reactions tend to occur in individuals who are allergic to peanuts, tree nuts, fish, and shellfish.  There are approximately 150 deaths each year in the US from food allergy, and over 90% of these are due to ingestion of peanuts and tree nuts.

How does one diagnose food allergy?

The symptoms of food allergy are quite variable, and almost any part of the body can be affected, including the skin, the circulatory system, the lungs, and the gastrointestinal tract.  Symptoms are due in large part to the release of histamine by the immune system as it attacks the particular food.  The excessive amounts of histamine that are released in the course of an allergic reaction to food can cause itching, hives, generalized swelling, wheezing, difficulty breathing, and even collapse of the circulatory system resulting in death.  Individuals can also develop nausea, abdominal cramping and pain, as well as vomiting and diarrhea.  Generally, allergic reactions to foods will occur shortly after (within seconds or minutes) of ingestion but can be delayed up to a couple of hours after the culprit food is consumed.  While most (approximately 80%) food allergy reactions are associated with itching and hives, it is important not to overlook food allergy in the absence of skin symptoms.  If the symptoms of a food reaction are suggestive of food allergy, an allergist may perform testing on the skin to confirm the diagnosis and to identify other related foods that could also lead to an allergic reaction if ingested.  A blood test, sometimes called a RAST test, may also be performed to document a food allergy.

Is there a cure for food allergy?

Unfortunately, there is currently no cure for food allergy, and treatment is centered on identification and avoidance of the culprit food.  However, some food allergies may resolve spontaneously given enough time.  For example, young children tend to “grow out” of allergy to milk, egg, soy, and wheat by the age of 3.  On the other hand, allergy to peanuts, tree nuts, or shellfish typically lasts for life.

Individuals with food allergy should be taught to read food labels carefully.  By law, any food product in the US containing peanuts, tree nuts, soy, shellfish, fish, cow’s milk, egg, and wheat must state this clearly on the label in common language.  At restaurants, if the customer is unsure about the ingredients of a particular menu item, it is important to ask the waitstaff or the cook.  One should also beware of buffets, where different foodstuffs are kept adjacent to one another and may inadvertently intermingle.  Teachers and other childcare providers should be made aware of the child’s food allergy, so they can help make the daytime environment safe.

Every individual with a food allergy should have a plan in place that describes actions to take in case of accidental ingestion.  The “Food Allergy Action Plan” should clearly identify the foods that cause the allergy, the symptoms of an allergic reaction, as well as the names and doses of medications that should be administered in case of an allergic reaction.  The Food Allergy Action Plan should also list the names and phone numbers of emergency contacts which should be notified after the 911 response system has been activated.

Where should one go for help with food allergy?

If an allergic reaction to a food is suspected, the first priority is to find immediate medical help and treat the current symptoms.  Afterward, your primary care physician or emergency department staff may wish to refer you to an allergist for confirmation of the diagnosis, as well as identification of other related foods that may cause similar reactions.  Your physician will review appropriate steps to take and make sure that you have the appropriate medicines with you to use in the instance of a repeat allergic reaction.

For more information, you can also contact the Food Allergy and Anaphylaxis Network at 800-929-4040 or at their website www.foodallergy.org.

Good luck, and happy eating!

 

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