Egg allergy is one of the more common pediatric food allergies. It typically affects just 0.5 percent of the pediatric population (less than 1 of every 100 children) and 5 of every 100 children with allergies. Reactions to egg can vary from life-threatening anaphylaxis to atopic dermatitis (eczema) to hives.
Food allergies are diagnosed by physical examination, previous experience, and allergy testing. There are two types of allergy testing: skin testing and blood testing for specific antibodies to eggs (commonly called RAST testing). Each test has advantages and disadvantages. In general, if you do not have a reaction in either test, you do not have an allergy to egg. However, the blood test can be negative in about 5 of every 100 children who actually do have an egg allergy. A positive blood or skin test indicates a potential to react to egg, and the larger the skin or blood test, the more likely it is that a reaction will occur.
Egg allergies and vaccines
Because influenza and yellow fever vaccines are both made in eggs, egg proteins (primarily ovalbumin) are present in the final products.
- Yellow fever vaccine — In the case of the yellow fever vaccine, quantities are sufficient to cause allergic reactions in susceptible patients. If you or your child is allergic to eggs and you are interested in getting the yellow fever vaccine, you should make an appointment with an allergist.
- Influenza vaccine — Advances in technology have allowed the quantities in current influenza vaccines given as shots to be so minimal that people with egg allergies can now receive the influenza shot. However, because very low quantities of egg protein are still present, people with egg allergy should remain in the provider’s office for about 30 minutes after receiving the vaccine. Two new influenza vaccines, one made in mammalian cells (not avian cells) and the other made using recombinant DNA technology, are now available for patients with egg allergies.
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Written by: Jonathan Spergel, MD, PhD
Dr. Spergel is Chief of the Allergy Section and Co-Director of the Center for Pediatric Eosinophilic Disorders at The Children’s Hospital of Philadelphia