Validation of a questionnaire algorithm based on repeated open application testing with the constituents of fragrance mix I.

The algorithm used in this study was not substantiated in this ROAT set-up. The stronger the patch test reactivity the more likely was a positive ROAT and the more likely it was that the positive ROAT appeared early during the application period. What's already known about this topic? To the best of our knowledge, a scientifically designed and conducted repeated open application test (ROAT) has never been performed before to validate a diagnosis of allergic contact dermatitis partly based on a questionnaire. What does this study add? This is the largest controlled, randomized and blinded ROAT performed to date. Higher patch test reactivity to fragrance mix I indicated a greater likelihood of a positive ROAT. What are the clinical implications of this work? Further refinement of the questions is required in order to diagnose allergic contact dermatitis from fragrances based on a questionnaire.