Can I have an allergic response the first time I'm exposed to an allergen?

Paul M. Ehrlich, MD
Allergy & Immunology
You only become allergic to things after you have already been exposed to them. An allergic response cannot take place upon first exposure to an allergen; sometimes that fact provides some very poignant glimpses into people's lives. For example, we once had a teenage patient from an observant Jewish family. His general practitioner had ordered a standard battery of radioallergosorbent test (RAST) tests and when son and father arrived to hear the results, I was chagrined to find a reaction to shrimp and lobster. These delicacies are not allowed under dietary laws observed by both devout Jews and Muslims, who are restricted to eating only kosher or halal foods, respectively. Ergo, it could only be that the son had tasted forbidden fruit of the sea.

In reviewing the results with them, my body language made the father suspicious and he asked to look at the printout himself. He said, "Doctor, it is my understanding that you only become allergic to things after you have already been exposed to them." I nodded. He turned to his son and spoke to him firmly but kindly in Yiddish. I couldn't contain my curiosity and asked him to tell me what he had said. He answered, "How did it taste?"
Asthma Allergies Children: A Parent's Guide

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Asthma Allergies Children: A Parent's Guide

Asthma and allergies are at epidemic proportions. It doesn't have to be that way. Two experienced pediatric allergists tell everything a conscientious parent needs to know about these conditions,...

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.