Patch Testing to Methyldibromoglutaronitrile/Phenoxyethanol: North American Contact Dermatitis Group Experience, 1994–2018

Abstract

BackgroundMethyldibromoglutaronitrile/phenoxyethanol (MDBGN/PE) is a broad-spectrum preservative mixture used in consumer and industrial products.ObjectivesThe aims of the study were (1) to characterize the prevalence and clinical relevance of patch test reactions to MDBGN/PE and the epidemiology of positive patients and (2) to determine the frequency of concomitant reactions of MDBGN/PE and its components.MethodsThis study used a retrospective analysis of cross-sectional data compiled by the North American Contact Dermatitis Group from 1994 to 2018.ResultsOf 55,477 tested patients, 2674 (4.8%) had positive patch test reactions to MDBGN/PE (1.0%–2.5% petrolatum [pet]); most were + (63.3%) or ++ (22.3%). Clinical relevance was considered definite in 3.0% and probable in 19.3% of reactions. Common dermatitis sites included the hands (26.4%), scattered/generalized distribution (24.7%), and the face (18.3%). Patients with a positive reaction to MDBGN/PE and/or MDBGN and/or PE were significantly more likely to be male and older than 40 years and/or had hand dermatitis (P ≤ 0.0033). Positivity to MDBGN/PE 2.0% pet decreased significantly over time (from 6.0% in 1998–2000 to 2.5% in 2017–2018, P < 0.0001). Personal care products were the most common exposure source (53.2%).ConclusionsOver time, positivity to MDBGN/PE 2.0% pet decreased significantly from 6.0% (in 1998–2000) to 2.5% (in 2017–2018). The high proportion of weak (63.3%) reactions underscore the need for careful interpretation of patch test sites. Important demographic associations included male sex and age older than 40 years.

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

“…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.…”