Doctor Betti Dr. Betti Hertzberg Ressler is a Board Certified Pediatrician on staff at Miami Children's Hospital. Dr. Hertzberg developed the toilet training video "Let's Go Potty." She is the co-author of "The Doctor's Book of Home Remedies for Children." Food allergies Question: I've read Dr. Marcus' discussion of food allergies ("They're not as common as you think") on the web site, but I'd like to know a little more about the process of reintroducing a suspected allergen to the diet. We'd like to get a ballpark figure for how long to wait before reintroducing the food, and how the food should be reintroduced. Our specific situation revolves around carrots and dairy products for a 20-month-old who hasn't been exposed to those foods for about 12 months. - Chris B.. Answer: We know that any substance (food or any foreign protein) can cause an allergic reaction. Depending on the type of response and the offending agent or cause i.e.: (local swelling from an ant bite or severe reactions from ingested food ), the body's immune system will respond and rise to the occasion. In the case of your child, it would be helpful to know if the symptoms were a true "allergic reaction" or just an intolerance. Keep in mind that a true allergy is one where the body reacts severely to the offending agent. For example, did your child develop hives or difficulty breathing? The term for this type of reaction is called anaphylaxis. It is a most severe form of allergy . If this is the type of reaction that your child had, I will recommend that you discuss the reintroduction of the foods you mentioned with your child's pediatrician who may then refer you to an allergist. If the "allergy" was not the severe type, but rather your child had symptoms such as diarrhea, skin rash or colic, it may be possible to slowly introduce the foods again. Please remember that if the body is sensitized (antibodies produced with a reaction during the first contact) to a particular substance, the next time contact is made with the same substance, the reaction may be far more severe. Just for the record, the milk protein vs. carrots is by far the most allergenic substance in the food group. It is usually the protein that gives us the most problems. Carrots are basically void of significant allergens, but everyone reacts differently. As for diary products, this food group has the majority of calcium that is needed for bones, teeth, blood vessels and a strong heart to mention a few. There are many foods that have good sources of calcium without the use of dairy per se. Soy, rice milk and supplements can all provide extra calcium. Always check with your child's doctor before introduction of any food that once caused a reaction. Or any question regarding your child's health. Enjoy your toddler! Dr. Betti Also see: Are vitamins reccommended for toddlers? Can a pediatrician comfortably prescribe and manage ADHD medication or is it better suited to a psychiatrist? More questions and answers Ask Dr. Betti your questions This information is not intended to be a substitute for visiting your pediatrician. If you or your child has specific concerns, you should see your doctor for a diagnosis and treatment.