Should methyldibromo glutaronitrile continue to be used in the European baseline Series? A REIDAC national cross‐sectional study

Abstract

Background Methyldibromo glutaronitrile (MDBGN) was one of the most frequent and relevant allergens found in patch testing at the beginning of this century. In 2008, this preservative was banned from cosmetics in Europe and ever since the prevalence of contact allergy to MDBGN has progressively decreased. Despite that gradual decline, MDBGN is still patch‐tested in most baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients, and the relevance of positive patch tests in a nationwide Spanish registry (REIDAC). Patients and methods We evaluated consecutively patch‐tested patients in all participating centres. Using these data, we calculated the proportion of patients with positive patch tests to MDBGN from June 2018 to June 2020 and evaluated the relevance of the positive patch tests. Results One hundred and fourteen out of 5072 (2.24 %) tested patients were sensitized to MDBGN. Clinical current relevance was confirmed in only one case. Conclusion Although the frequency of contact allergy to MDBGN remains high, no clinical significance was found in most of these patients (5072 tests needed to obtain one relevant positive result). The clinical usefulness of this allergen seems weak and its continued inclusion in the European baseline series is questionable.

Arguments in favour of excluding MDBGN from the European baseline series. In response to “Comment on MDBGN/DBDCB, the European baseline series, and EU legislation”

“…The results of several epidemiological European studies including ours [4][5][6] showed a declining trend in the frequency of contact allergy to MDBGN in Europe since its banning from cosmetics, indirectly reflecting a good compliance with the regulatory guidelines by manufacturers. This declining trend was especially evident when we stratified by age groups, 2,6 with the younger individuals significantly showing the lower frequency of positive tests. Accordingly, we only found one positive test involving one patient out of 343 tested (all under the age of 20 years).…”

“…To the Editor, We would like to thank Lidén and White for their "Comment on MDBGN/DBDCB, the European baseline series, and EU legislation" 1 regarding our publication 2 and their thorough and accurate review about legislation concerning methyldibromo glutaronitrile (MDBGN) in Europe. We are aware that the information about the current status of legislation was not provided in our article; however, such a type of review was beyond the scope of our research.…”

Comment on MDBGN/DBDCB, the European baseline series, and EU legislation

“…Some authors, when unable to confirm current relevance based on label information, have suggested that most reactions are irritant, doubtful, false-positive, or of only past relevance. 1,[3][4][5][6][7] Some authors have even recently suggested that MDBGN/ DBDCB be deleted from the European baseline series, 1,3,4 and it has been decided by the American Contact Dermatitis Society to that the substance be removed from its core allergen series, 6 despite relatively high prevalence of contact allergy. 1,[8][9][10] We consider that omitting the substance from the baseline series, instead of tracking exposure more efficiently, will harm surveillance and prevention of skin sensitization and allergic contact dermatitis.…”

Reply to further response: Comment on MDBGN/DBDCB, the European baseline series, and EU legislation—Again

“…In response to "Comment on MDBGN/DBDCB, the European baseline series, and EU legislation", 1 replied to our Letter to the Editor 2 regarding their recent paper. 3 In their reply, 1 Mercader-García et al avoid the key points of concern in our Letter to the Editor 2 :1. We do not think and have not suggested that there is currently widespread or uncontrolled use of methyldibromo glutaronitrileHowever, we are concerned that use, sensitization, and elicitation will increase owing to the ongoing global campaign by LANXESS marketing MDBGN/DBDCB.…”

“…In response to "Comment on MDBGN/DBDCB, the European baseline series, and EU legislation", 1 replied to our Letter to the Editor 2 regarding their recent paper. 3 In their reply, 1 Mercader-García et al avoid the key points of concern in our Letter to the Editor 2 :…”