Background: Immediate-type wheat allergy due to hydrolyzed wheat protein (HWP-IWA) supplemented soap has been a serious social issue. We investigated the significance of challenge test and other tests not only to diagnose HWP-IWA but to know the symptoms of each patients.
Methods: From January 2010 to June 2012, we performed challenge test in 41 cases with positive prick test of Glupearl 19S®, a major allergic HWP found in Cha no Shizuku®.
Results: Thirty nine of 41 cases were challenge test positive. In two patients who showed positive skin prick test but negative for challenge test, titer of specific IgE antibody and/or basophil histamine release test against Glupearl 19S® revealed positive reaction.
Conclusion: Challenge test is not included in indispensable examinations for the diagnosis of HWP-IWA in the recommended guidelines. However, challenge test is still a useful tool for assessing actual severity of each patient's symptoms and determining the timing of cessation of wheat avoidance. In addition, combined check-up with several laboratory examination and challenge test may help appropriate diagnosis of HWP-IWA.