Compendium of the most significant studies with reference to properties, intake, effects.

Schnuch A, Schubert S, Lessmann H, Geier J; IVDK. The methylisothiazolinone epidemic goes along with changing patients' characteristics - After cosmetics, industrial applications are the focus. Contact Dermatitis. 2020 Feb;82(2):87-93. doi: 10.1111/cod.13414.

Abstract.  After an unprecedented epidemic of MI allergy, mainly caused by its use in cosmetics, the continuous use of MI in industrial applications, for example, paints, and subsequent sensitization remain a matter of concern.

Uter W, Aalto-Korte K, Agner T, Andersen KE, Bircher AJ, Brans R, Bruze M, Diepgen TL, Foti C, Giménez Arnau A, Gonçalo M, Goossens A, McFadden J, Paulsen E, Svedman C, Rustemeyer T, White IR, Wilkinson M, Johansen JD; European Environmental Contact Dermatitis Research Group. The epidemic of methylisothiazolinone contact allergy in Europe: follow-up on changing exposures. J Eur Acad Dermatol Venereol. 2020 Feb;34(2):333-339. doi: 10.1111/jdv.15875.

Abstract.  The prevalence of MI contact allergy decreased by 50% from 2015 to 2017. As a consequence of regulation, the share of cosmetics products (leave-on in particular) eliciting allergic contact dermatitis is decreasing. The chosen method of analysing causative products in sensitized patients has proven useful to monitor effects of intervention.

Burnett CL, Boyer I, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Gill LJ, Heldreth B. Amended Safety Assessment of Methylisothiazolinone as Used in Cosmetics. Int J Toxicol. 2019 May/Jun;38(1_suppl):70S-84S. doi: 10.1177/1091581819838792. 

Abstract. The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of methylisothiazolinone (MI), which functions as a preservative. The Panel reviewed relevant animal and human data provided in this safety assessment and in a previously published safety assessment of MI and concluded that MI is safe for use in rinse-off cosmetic products at concentrations up to 100 ppm and safe in leave-on cosmetic products when they are formulated to be nonsensitizing, which may be determined based on a quantitative risk assessment.

Leiva-Salinas M, Francés L, Silvestre JF. Update on allergic contact dermatitis due to methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone. Actas Dermosifiliogr. 2014 Nov;105(9):840-6. English, Spanish. doi: 10.1016/j.ad.2013.12.010.

Abstract. Furthermore, our data indicate that MCI/MI at 200 ppm would make it possible to diagnose more cases of contact allergy to MI. To improve the diagnosis of contact allergy to MCI/MI and MI, we believe that the test concentration of MCI/MI should be increased to 200 ppm in the GEIDAC standard series and that MI should be added in the GEIDAC standard series.

Lachapelle JM. Methylisothiazolinone: the new star of contact dermato-allergology. J Eur Acad Dermatol Venereol. 2020 Feb;34(2):218. doi: 10.1111/jdv.16174.

Park EJ, Seong E. Methylisothiazolinone induces apoptotic cell death via matrix metalloproteinase activation in human bronchial epithelial cells. Toxicol In Vitro. 2020 Feb;62:104661. doi: 10.1016/j.tiv.2019.104661.

Abstract. Taken together, we conclude that MIT induces apoptotic cell death and inflammatory response by activating MMPs in BEAS-2B cells. We also suggest that further study is necessary to clarify the possible carcinogenesis of MIT.