Patch Test and Specific IgE Level with Food Antigens in Atopic Dermatitis Patients

Chang, Dae Sung; Seo, Seong Jun; Hong, Chang Kwun

Abstract

BACKGROUND: Food allergies have been demonstrated to play an important role in the pathogenesis of atopic dermatitis(AD), affecting around 10 to 40% of patients with AD. While immediate-type clinical reactions to food can easily be identified, the evaluation of a food allergy in the absence of immediate clinical reactions still presents diagnostic difficulties.
OBJECTIVE
The purpose of this study was to evaluate the diagnostic value of the atopy patch test with regard to late-phase reactions and to evaluate the relationship between patch test and specific serum IgE level.
METHODS
We performed the patch test and chemiluminescent assay(CLA) for food antigens(cow's milk, soybean milk and hen's egg) in 45 patients with AD who were suspicious of food-related symptoms and 15 normal controls.
RESULTS
1. Positive reaction of CLA in 45 patients with AD were 7/18(38.9%) for the cow's milk, 5/14(35.7%) for the soybean milk and 4/13(30.7%) for the hen's egg. 2. Positive reaction of the patch test in patients with AD were 5/18(27.8%) for the cow's milk, 6/14(42.9%) for soybean milk and 4/13(30.7%) for hen's egg, but only one(6.7%) for cow's milk in 15 normal controls. 3. A highly significant correlation to food antigens existed between patch test and CLA, but one patient showed a positive reaction in the patch test for soybean milk despite the negative reaction in CLA. 4. There was no significant statistical correlation between the severity of AD and the positive reaction rate of the patch test. 5. There were no significant statistical differences between the age of AD patients and the positive reaction rate of the patch test.
CONCLUSION
The atopy patch test seems to be a valuable tool in the diagnostic work-up of food allergies in patients with AD-especially with regard to late-phase clinical reactions.