Introduction to Food Allergy
- About 2.2 million children or 8% of children in the US are estimated to have food allergies while only 2% of adults have food allergies.
- The incidence of food allergy is rising and unfortunately, we don’t know exactly why this is happening.
What is a food allergy?
- A food allergy is produced when your immune system overreacts to certain proteins in foods. Specifically, an allergic antibody called IgE thinks a certain protein in a food is foreign and fights against it.
- This causes a cascade of events in a food allergic person’s body which may include:
- Rash – Hives are the most common allergic skin reaction to a food. Hives are red, raised, itchy areas of the skin which appear in clusters on the skin and usually do not stay in one place on the skin for more than 24 hours. Eczema, which is a more chronic skin problem characterized by itchy, red, scaly skin can also occur.
- Mouth/Throat symptoms – itching, tingling, or swelling of the lips, tongue, throat, or mouth
- Chest symptoms – SOB, repetitive coughing, or wheezing
- Gastrointestinal symptoms – nausea/vomiting, diarrhea, or abdominal cramping
- Heart – weak pulse, low blood pressure, fainting, paleness
- Anaphylaxis is the term we use to describe a severe, life threatening allergic reaction which produces symptoms in two or more body systems
What are the most common food allergens?
- Milk, egg, wheat, peanut, tree nuts, and soy make up 90% of all food allergies in children.
- In adults, fish and shellfish are high on the list of food allergens as well.
- We’ve been hearing more and more about peanut and other nut allergies which tend to produce some of the most serious, life threatening reactions. Whereas milk and egg allergies in children are most likely to be outgrown by age 5, only about 20% of nut allergies are outgrown.
How are food allergies diagnosed?
- An allergist/immunologist is the most qualified person to help you with this diagnosis.
- Skin testing is helpful in making a diagnosis of food allergy. A small amount of liquid extract of the food being tested is placed on the back or the forearm and a small needle makes a prick through the drop of liquid. If the tested area of skin gets red and swollen, a diagnosis of possible food allergy can be made.
- Blood tests can also be helpful in making the diagnosis. We can do food specific IgE antibody testing which is also a good diagnostic tool. For some food allergies, the food specific IgE level can determine what the likelihood is of a future reaction to that particular food.
- Occasionally, we do food challenges in the office to confirm that a patient does NOT have a food allergy. Of course, this is best done in the doctor’s office, under the supervision of a qualified physician.
What is the treatment?
- Avoidance of known food allergens is the best way to prevent reactions from occurring. It is important to read labels and ask restaurants for a complete list of ingredients before ingesting foods.
- All people with food allergies should carry an epipen with them at all times. An epipen is an adrenaline self-injectable that can be used in case of accidental ingestion of a known allergen. There are a number of videos on in internet on how to use EpiPen. One of them is: https://www.epipen.ca/en/about-epipen/how-to-use
- All people with food allergies should also wear an ID bracelet stating all their food allergies clearly.
- For children with food allergies, school personnel including the teachers, administrators, and school nurses should be aware of the allergy and know how to use an epipen correctly.
When should I see an allergist/immunologist?
- An allergist can help you with the diagnosis of food allergy and also help follow the food allergy over time to see if it is outgrown.
- We can also provide additional resources to make living with food allergy a little easier and less nerve racking.
- Two great resources are the Food Allergy and Anaphylaxis Network and the Food Allergy Initiative.