Diagnostic accuracy of the atopy patch test and the skin-prick test for the diagnosis of food allergy in young children with atopic eczema/dermatitis syndrome

Aim: To evaluate the diagnostic value of the skin-prick test and the atopy patch test in diagnosing basic food allergy in young children suffering from atopic eczema/dermatitis syndrome. Methods: 141 children, the majority under 2 y of age (mean 16 mo) with atopic eczema/dermatitis syndrome were investigated using skin-prick and atopy patch tests for milk, egg, wheat and rye. Open diagnostic elimination challenge was done since this has been reported to be a reliable method in young children. Results: A positive challenge response was found to milk in 63 (45%), egg in 78 (55%), wheat in 61 (43%) and rye in 61 (43%). Sensitivity/specificity of the atopy patch test was 60%/97% for milk, 71%/97% for egg, 90%/94% for wheat and 93%/90% for rye. For the skin-prick test the corresponding figures were 41%/99%, 60%/97%, 13%/98% and 15%/99%. Conclusion: Patch testing was found to be a more sensitive method than the skin-prick test in diagnosing food allergy in children with atopic eczema/dermatitis syndrome, especially in those under 2 y of age. Many children with a negative skin-prick test result have a positive patch test result, especially in the case of cereals. A diagnosis of food allergy should be confirmed by elimination and in the research setting also by challenge.