Trends in the Prevalence of Methylchloroisothiazolinone/Methylisothiazolinone Contact Allergy in North America and Europe

Abstract

ImportanceThe common use of isothiazolinones as preservatives is a global cause of allergic contact dermatitis. Differences in allowable concentrations of methylisothiazolinone (MI) exist in Europe, Canada, and the US.ObjectiveTo compare the prevalence of positive patch test reactions to the methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) combination and MI alone in North America and Europe from 2009 to 2018.Design, Setting, and ParticipantsThis retrospective analysis of North American Contact Dermatitis Group, European Surveillance System on Contact Allergies (ESSCA), and the Information Network of Departments of Dermatology (IVDK) databases included data from patients presenting for patch testing at referral patch test clinics in North America and Europe.ExposuresPatch tests to MCI/MI and MI.Main Outcomes and MeasuresPrevalence of allergic contact dermatitis to MCI/MI and MI.ResultsFrom 2009 to 2018, participating sites in North America and Europe patch tested a total of 226 161 individuals to MCI/MI and 118 779 to MI. In Europe, positivity to MCI/MI peaked during 2013 and 2014 at 7.6% (ESSCA) and 5.4% (IVDK) before decreasing to 4.4% (ESSCA) and 3.2% (IVDK) during 2017 and 2018. Positive reactions to MI were 5.5% (ESSCA) and 3.4% (IVDK) during 2017 and 2018. In North America, the frequency of positivity to MCI/MI increased steadily through the study period, reaching 10.8% for MCI/MI during 2017 and 2018. Positive reactions to MI were 15.0% during 2017 and 2018.Conclusions and RelevanceThe study results suggest that in contrast to the continued increase in North America, isothiazolinone allergy is decreasing in Europe. This trend may coincide with earlier and more stringent government regulation of MI in Europe.

Systematic Identification of Copositivity Groups in Standard Series Patch Testing Through Hierarchical Clustering

“…MCI and MI are preservatives with elevated positivity rates in North America, but recently decreasing in Europe . Notably, MCI/MI contains MI, resulting in a known strong association .…”

“…Methylchloroisothiazolinone/ Methylisothiazolinone (MCI/MI) and Bronopol Group MCI and MI are preservatives with elevated positivity rates in North America, but recently decreasing in Europe. 1,43 Notably, MCI/MI contains MI, resulting in a known strong association. [44][45][46] Here, we found that MCI/MI and MI were strongly copositive (35.0-36.9)%.…”

New causes of occupational allergic contact dermatitis

“…This may be due to more stringent government regulation of methylisothiazolinone in Europe in recent years. In North America, both MCI/MI and methylisothiazolinone continue to have a high prevalence of positive patch test reactions [38 ▪ ]. MCI/MI and methylisothiazolinone continue to be reported sources for occupational ACD in mechanics, hairdressers, cleaners, healthcare workers and industrial workers exposed to these preservatives in rubber, metalworking fluids, cutting fluids, cooling liquids, adhesives and paints [39,40].…”

Artificial Intelligence That Predicts Sensitizing Potential of Cosmetic Ingredients with Accuracy Comparable to Animal and In Vitro Tests—How Does the Infotechnomics Compare to Other “Omics” in the Cosmetics Safety Assessment?

“…Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 states that “a cosmetic product made available on the market shall be safe for human health when used under normal or reasonably foreseeable conditions of use” [ 4 ]. Epidemiological data confirm that regulatory restrictions on the use of ingredients with known sensitizing properties can result in a reduction of sensitization rates [ 5 ]. This positive effect may be partly hampered by the fact that cosmetic products sometimes contain undeclared (“hidden”) ingredients or contaminants with possible adverse effects going beyond of what would be expected based on their declared content [ 6 , 7 ].…”

“…On 11 March 2009, an unconditional ban on all tests of cosmetics ingredients on animals was introduced in the EU with the exception of toxicokinetics, repeated dose toxicity, and reproductive toxicity studies. Finally, on 11 March 2013, a total ban on testing cosmetics ingredients and finished cosmetics in animals has come into force, along with a ban on the placing products tested on animals on the market, regardless of the availability of alternative methods ( Table 1 ) [ 5 ].…”