Eigenmenn PA, Sicherer SH, Borkowski TA, Cohen BA, Sampson HA. Pediatrics. 1998;101(3). URL: http://www.pediatrics.org/cgi/content/full/101/3/e8
Purpose of the Study
Although it is clear that food allergy may play an important role in atopic dermatitis (AD) in selected populations, its overall prevalence in children with eczema is still not fully established. This study was designed to study the prevalence of immunoglobulin E (IgE)-mediated food allergy in children with atopic dermatitis being seen in a pediatric dermatology clinic.
Sixty-three patients with AD, ranging in age from 0.4 to 19.4 years (median, 2.8 years).
Each patient's AD was scored by a standardized protocol and serum was screened for food-specific IgE antibodies to six foods (milk, egg, wheat, soy, peanut, and fish). Those with CAP radioallergosorbent (RAST) tests greater than 0.7 kIUa/L underwent further evaluation and were considered to be food allergic if they had: 1) a positive food challenge; 2) a convincing history of reacting to the food to which the RAST was positive; and 3) a CAP RAST level greater than the 95% confidence interval predictive for a positive challenge.
Of the 63 patients, 22 had negative CAP values and were considered to not be food allergic. Of the 41 with one or more positive tests, 31 were evaluated further, including a total of 50 food challenges in 19 patients. Overall, 23 of the 63 (37%) patients were found to have a clinically significant food allergy.
Approximately one third of children with moderate to severe AD have IgE-mediated clinical reactivity to one or more of the six food allergens tested. An evaluation for food allergy should be considered in all patients with difficult to control AD.
Previous studies looking at the relationship between food allergy and AD have primarily been performed in patients referred to an allergy clinic and therefore may have been biased toward a more allergic population. This study, conducted in a dermatology clinic, helps to confirm the high prevalence of food allergy in children with significant AD, no matter where they are being seen. An evaluation for food allergy in this population has a high yield and should not be overlooked. It should also be noted that screening for food allergy is a relatively simple process, as described in the abstract below, while making a definitive diagnosis of food allergy can be a complicated process that will require referral to an allergist experienced with food allergy and capable of performing food challenges.