Q: I often have people say that, “unlike your son, my child’s allergy is not that severe.” My understanding is that there is no way to know if a reaction will be life-threatening, regardless of past reaction experience. What do you advise saying to people who believe an allergy is “not severe”?
Dr. Sharma: You are absolutely correct – prior food allergy reactions cannot be relied on to predict the severity of future ones.
For those who believe an allergy is “not severe,” this point may be underscored by the fact that most people who have died because of food-allergic anaphylaxis have had prior reactions, but these were rarely serious.
The severity of an individual reaction depends on many factors. These include the amount of the food consumed, the form of the food, and presence of illness or exercise at the time of ingestion.
Antibodies Don’t Predict Severity
There is great interest in identifying forms of testing that could predict allergy severity. Unfortunately, the test level of IgE antibodies to a certain food do not accurately predict the potential severity of future reactions.
However, research suggests that for some allergens, such as peanut, component testing can help to distinguish between those likely to have a reaction limited only to the mouth and throat versus a widespread anaphylactic reaction. Component testing identifies IgE levels to different parts of the peanut protein.
Other forms of testing under study, such as basophil activation testing, may in the future allow us to predict reaction severity with more accuracy.
Until then, it is important to understand the unpredictable nature of food allergy – and to always carry epinephrine and be prepared in case of a severe reaction. It is also important to spread this knowledge.
Dr. Sharma is an allergist, clinical researcher and associate professor of pediatrics. He is Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington D.C. and Director of the Food Allergy Program. He co-authors “The Food Allergy Experts” column in Allergic Living e-magazine. Questions submitted will be considered for answer in the magazine.Submit a Question View all posts by this medical expert.