MAUI, HAWAII – Current thinking on the role of food allergy in pediatric atopic dermatitis suggests a greatly diminished role for allergy testing compared with times past, according to Dr. Joseph F. Fowler Jr.
Guidelines issued by a National Institute of Allergy and Infectious Diseases expert consensus panel – mostly allergists, with little input from dermatologists – concluded that food allergy is actually fairly uncommon in atopics. It affects less than 10% of children under age 2 who have eczema, and a far smaller percentage of older atopic children.
Dr. Joseph F. Fowler
Moreover, the voluminous 58-page report (J. Allergy Clin. Immunol. 2010;126:S1-58) makes the point that allergy testing is time consuming, costly, and not terribly reliable due to high false-positive rates for both scratch testing and RAST (radioallergosorbent tests).
"The bottom line on all this is you probably don’t need to do food allergy testing very often at all in atopics because in those few who did have an allergy to foods, the big three – eggs, milk, and peanuts – accounted for the vast majority of food allergy. So if you’re not sure, what you can do is eliminate those three from the diet, then add them back in one at a time after a few weeks of elimination. That ought to give you a sense of whether there’s really and truly a food allergy operative in that individual," Dr. Fowler said at the Hawaii Dermatology Seminar sponsored by Global Academy for Medical Education/Skin Disease Education Foundation.
"It’s true that occasionally you see allergy to wheat or fish or chocolate or soy or who knows whatever else, but all those other things are very, very uncommon. So while I wouldn’t say you should never do food allergy testing or send a little atopic with recalcitrant eczema for food allergy testing, I think the yield is really going to be relatively low. Doing the elimination trial first is probably the best thing. A good, motivated, observant caregiver is going to be more informative than what the test will tell you," said Dr. Fowler, clinical professor of dermatology at the University of Louisville (Ky.) and codirector of the SDEF seminar.
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Dr. Fowler is on the speakers bureaus of Galderma, Ranbaxy, and SmartPractice and has received research grants from numerous pharmaceutical companies.