BACKGROUND: The preservative methylisothiazolinone (MI) has become an important allergen, with a dramatic increase in sensitization prevalence being seen over the last few years. OBJECTIVE: To examine risk factors associated with MI sensitization, in order to identify targets of prevention aimed at curtailing the present epidemic. METHODS: On the basis of contact allergy surveillance data collected by the Information Network of Departments of Dermatology (www.ivkd.org), 2009-2012, in the course of 28,922 patch tests with MI, 500 ppm in water, included in a series of cosmetic preservatives, logistic regression analysis was employed to quantify the risk associated with a number of putative risk factors. RESULTS: The prevalence of MI sensitization increased from 1.94% in 2009 to 6.02% in 2012, the increase being mainly driven by female patients aged≥ 40 years, patients with face dermatitis, and the use of cosmetics. Adjusted multifactorial analysis additionally identified several occupations (e.g. painters and beauticians) and ano-genital dermatitis as risk factors for MI sensitization. CONCLUSIONS: The present use concentrations of MI, both cosmetic and industrial, are too high; (self-)regulatory action is urgently needed. MI should be added to the baseline series.
BACKGROUND: The preservative methylisothiazolinone (MI) has become an important allergen, with a dramatic increase in sensitization prevalence being seen over the last few years. OBJECTIVE: To examine risk factors associated with MI sensitization, in order to identify targets of prevention aimed at curtailing the present epidemic. METHODS: On the basis of contact allergy surveillance data collected by the Information Network of Departments of Dermatology (www.ivkd.org), 2009-2012, in the course of 28,922 patch tests with MI, 500 ppm in water, included in a series of cosmetic preservatives, logistic regression analysis was employed to quantify the risk associated with a number of putative risk factors. RESULTS: The prevalence of MI sensitization increased from 1.94% in 2009 to 6.02% in 2012, the increase being mainly driven by female patients aged≥ 40 years, patients with face dermatitis, and the use of cosmetics. Adjusted multifactorial analysis additionally identified several occupations (e.g. painters and beauticians) and ano-genital dermatitis as risk factors for MI sensitization. CONCLUSIONS: The present use concentrations of MI, both cosmetic and industrial, are too high; (self-)regulatory action is urgently needed. MI should be added to the baseline series.