New Allergy Tests May Help Improve Life for People With Food Allergies

By Dr. Paul Ehrlich

One of our little catch phrases for why we have a website to go with our book is that medical science moves faster than print. I had the chance to see that in action recently at a grand rounds at Mt. Sinai Hospital where Dr. Magnus Wickman of the Karolinska Institute in Sweden talked about new testing techniques that allow us to find out which individual proteins in peanuts, or hazel nuts, or various fruits a patient is seriously allergic to.

These allergens are there for a reason. They help make a tomato a tomato or a peach a peach. Some of them provide protection against pests, or store nutrients vital to development and growth. And some of these proteins are found in very different fruits or vegetables. Like animals, plants have evolved from common ancestors. You might say nature doesn’t want to reinvent the wheel either. So some nasty-tasting protein that keeps insects or birds from eating unripe fruit may be found in lots of other foods as well.

Thus, the full complex of proteins that make a peanut a peanut (and highly allergenic), will not appear in tree nuts, too. But there will be just enough of them to provoke a minor allergic cross-reaction. In a “normal” set of allergy tests, which shows both reactions, a “normal” doctor might say, don’t eat either one, or, as frequently happens, don’t eat ALL of them. However, because banishing a large number of foods from your diet can make it hard to maintain good health, Dr. Chiaramonte and I have long helped patients negotiate this minefield based on our clinical experience. As I have written previously, I regularly see kids who can’t gain appropriate levels of weight. They are malnourished. As they grow older, many of these children have eating disorders because they have grown up with a well-intentioned Mom worrying about what they eat all the time.

It can also make life less fun. Dr. Wickman shares my interest in the patient’s quality of life. He speaks with sadness about teenagers who are afraid of the world because they are worried about accidental exposures. He is using the new tests to help such kids emerge from their fear bubble and eat more freely.

The new tests may be good tools, better tools in fact, than we ever dreamed of when we did our training. In fact, in my office we have been using them, too. However, in our experience, they will not replace the clinical judgment based on a good medical history of a good doctor, at least not any time soon, although we do have to learn how to use them wisely.

(To learn more about the new tests, called ImmunoCap, click here.)