Recommendation to include methylisothiazolinone in the European baseline patch test series--on behalf of the European Society of Contact Dermatitis and the European Environmental and Contact Dermatitis Research Group
Bruze, Magnus × Engfeldt, Malin Gonçalo, Margarida Goossens, An #
Contact Dermatitis vol:69 issue:5 pages:263-270
BACKGROUND: Methylisothiazolinone (MI) is used as a preservative in occupational and household products, and cosmetics. It is a part of the preparation of methylchloroisothiazolinone (MCI)/MI, which is patch tested in water in the European baseline series. However, this preparation fails to detect a significant percentage of allergic contact reactions to MI.
OBJECTIVES: To investigate whether a separate test preparation with MI should be included in the European baseline series.
METHODS: Literature survey.
RESULTS: In consecutively tested dermatitis patients, the contact allergy rate for MI varies between 0.6% and 6%, with a marked increase in recent years. The contact allergy rate for MI alone, not detected with MCI/MI, varies between 0% and 1.6%. Most cases are relevant, as shown by repeated open application test studies, and are mainly related to exposure from cosmetic products.
CONCLUSIONS: Owing to the increase in contact allergy to MI not detected with MCI/MI, it is recommended that MI in water at 2000 ppm be included in the European baseline series. With the Finn Chamber(®) (diameter, 8 mm) technique, a volume of 15 µl should be applied, giving a dose of 60 µg/cm(2).