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Original Article


Usefulness of the Skin Index in Predicting the Outcome of Oral Challenges in Children


H Ueno,1 K Yoshioka,2 T Matsumoto1

1.-Department of Child Development, Graduate School of Medical Sciences, School of Medicine, Kumamoto University,
Kumamoto, Japan
2.-Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan

J Investig Allergol Clin Immunol 2007; Vol. 17(4): 207-210



Background: The diagnostic accuracy of the skin prick test (SPT) for food allergies remains to be fully accepted and substantial individual differences in the prevalence of skin test reactivity have been reported.

Objective: The aim of this study was to assess the diagnostic value of absolute wheal size and skin index (SI; ratio of food allergen-induced wheal to histamine-induced wheal) according to the outcome of controlled oral food challenges.

Methods: Eighty-seven controlled oral challenges were performed with cow’s milk, hen eggs, wheat, buckwheat, peanuts, seafood, and/or fruit in 51 children (median age, 35 months). The wheal diameters in SPT, the SI, and the serum specific immunoglobulin (Ig) E concentrations were determined.

Results: Thirty-three oral challenges were assessed as being positive. SI and wheal diameter in SPT were both signifi cantly different according to the outcome of food challenge (P<.001 and P = .03, respectively); the greatest difference was found in the case of SI. Serum specific IgE concentration did not differ signifi cantly according to the outcome of food challenge.

Conclusion: SI may be helpful for predicting a positive outcome of food challenge.

Key words: Skin prick test. Food allergy. Oral food challenge.