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

Abstract

Summary Background In a European study on contact allergy in the general population, it was hypothesized that the combination of contact allergy to a fragrance together with a history indicating dermatitis at exposure, and thereafter subsequent avoidance of scented products, implied a diagnosis of allergic contact dermatitis. Objectives The primary aim of this study was to validate this hypothesis and algorithm. The secondary aim was to investigate whether there was any association between the outcome of the repeated open application test (ROAT) and the patch test reactivity. Methods In total, 109 patients with and without contact allergy to fragrance mix (FM) I were recruited. Volunteers from six European dermatology clinics participated in the study including a patch test and a ROAT. Results Positive ROAT reactions were noted in 26 of the 44 volunteers with contact allergy to FM I. None of the volunteers reacted to the vehicle (P < 0·001). More individuals with a positive algorithm had positive ROATs than those with a negative algorithm. However, the difference was not statistically significant. The lower the patch test concentration eliciting a positive test reaction, the more likely a positive ROAT and the more likely that the positive ROAT appeared early during the investigative period. Conclusions 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.

Validation of questionnaire algorithm based on repeated open application testing with the constituents of fragrance mix II: the EDEN Fragrance Study

“…4,5 When this algorithm was investigated in a recent repeated open application test (ROAT) with the ingredients of fragrance mix (FM) I, it was not substantiated in the experimental setup used. 12 The primary aim of this study was to validate the hypothesis that a positive history defined as dermatitis at exposure to a scented product and thereafter avoidance of such products in individuals hypersensitive to FM II is equivalent with allergic contact dermatitis from fragrances. The secondary aim was to investigate whether there was any association between the outcome of the ROAT and the individual degree of patch test reactivity.…”

Patient recall may be of limited use in establishing the clinical relevance of positive patch test reactions (to fragrances)

“…Thirdly, combining, as the authors did, the patch test results of 2011 and 2014 in a ‘believe the positive’ fashion, arriving at 44 participants allergic to FM I, 26 of 29 positive ROATs were seen in these 44 . This translates to a positive predictive value (PPV) of 59%.…”

“…In this issue of the BJD , Bruze et al . present results from the largest repeated open application test (ROAT) follow‐up study ever, involving 40 patients with a previous positive patch test reaction to FM I compared with 68 controls with negative reactions to FM I, all obtained during the 2011 European Dermato‐Epidemiology Network (EDEN) fragrance study .…”

“…Thereby, valid and reliable patch test outcomes had been amalgamated with relatively ‘soft’ self‐reported data, which I criticized at the time . The limited usefulness of referring to such self‐report, and outcomes based on it, has now been confirmed …”

“…Evidently, full ingredient information (in labelling) beyond cosmetics would also be of great benefit to both doctor and patient. Illustrating the shortcomings of human memory in this special context, the study by Bruze et al . provides an important argument for us dermatologists in our quest for full product information.…”