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Information from AAFA’s Ask the Allergist is not a substitute for a consultation with a health care professional. Always talk with your own doctor before making changes to your asthma or allergy management plan.

This question appeared in our spring/summer 2020 issue of freshAAIR Magazine, our FREE digital magazine featuring news and resources on asthma and allergies. Read the most recent issue.

Question: If you haven’t eaten a food in a couple of years and then try it again, does that increase your chances of developing an allergy to that food? Is it possible for a first allergic reaction to a food to be anaphylaxis? (Anaphylaxis is a severe allergic reaction that can be life-threatening.)

Answer: For an adult, the risk would be very low, but it is possible. For adults, new food allergy triggers are more likely to be nuts and seafood. For young children, it is possible to have an allergic reaction the first time they eat the food. This is one of the reasons allergists recommend early exposure to peanut in the first year of life for those who are at a higher risk (children with an egg allergy and severe eczema). In this case, eating the food regularly helps lead to food tolerance and a decreased risk of allergic reactions.

Dr. Douglas Johnston is our Ask the Allergist columnist. Dr. Johnston is a board-certified allergist/immunologist with Asthma & Allergy Specialists, P.A., in Charlotte, North Carolina. He obtained his D.O. from New York Institute of Technology College of Osteopathic Medicine. He completed his residency at Winthrop University Hospital in Mineola, New York. Dr. Johnston grew up with both allergies and asthma. He decided it would be exciting to help people with these conditions. His passion about food allergies also comes from having a child with a peanut allergy. 

“AAFA’s Ask the Allergist” is a free service provided by the Asthma and Allergy Foundation of America (AAFA). Kids With Food Allergies is a division of AAFA. Our allergist will answer your questions about managing asthma or allergies and medicines and treatments. Submit your question on our website.


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That's a great questions ToniMareeC! The main studies have been regarding the introductions of peanuts and there hasn't been a lot of new information released since the 2017 studies.

I did find this from the American Academy of Pediatrics:

AAP Clinical Report Highlights Early Introduction of Peanut-based Foods to Prevent Allergies

“There is no reason to delay giving your baby foods that are thought of as allergens like peanut products, eggs or fish,” said Dr. Scott Sicherer, MD, FAAP, a coauthor of the report. “These foods can be added to the diet early, just like foods that are not common allergens, like rice, fruits or vegetables.”

One thing to keep in mind is that all kids are different. It's always best to check in with your child's doctor about food introductions especially since your child has a history of food allergies.

Kathy P

Thanks for the info! Just wondering - in the example of peanut, I’ve been told to continue to give a teaspoonful twice a week (After we cautiously introduced it without any issues).. Is there any info to suggest it would matter if you give less than this, or if the teaspoonful is somewhat spread throughout the day/over a few days? (Babies can be so temperamental with eating!). 
Would you suggest doing this also with fish and legumes (giving them twice weekly)? 
(my baby is allergic to eggs, milk and maybe treenuts so am keen to do what I can to help prevent additional allergies!). Kind regards

Last edited by ToniMareeC
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