Epidemic of isothiazolinone allergy in North America: Prevalence data from the North American contact dermatitis group, 2013-2014

Matthew J. Zirwas, Dathan Hamann, Erin M. Warshaw, Howard I. Maibach, James S. Taylor, Denis Sasseville, Joel G. DeKoven, Anthony F. Fransway, C. G.Toby Mathias, Kathryn A. Zug, Vincent A. DeLeo, Joseph F. Fowler, James G. Marks, Melanie D. Pratt, Donald V. Belsito

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Background: Preservative sensitivity patterns evolve with changing use patterns in products. During the last decade, the use ofmethylisothiazolinone (MI) at higher concentrations in both leave-on and rinse-off products has significantly increased. This is the first North American Contact Dermatitis Group reporting cycle that includes both methylchloroisothiazolinone (MCI)/MI and MI data. Objective: The aim of this study was to report the prevalence of isothiazolinone allergy (MCI/MI and MI) in the North American Contact Dermatitis Group patch-test population from January 1, 2013, to December 31, 2014. Methods: At 13 centers in North America, 4860 patients were patch tested in a standardized manner with a series of 70 allergens, including MCI/MI 0.01% aqueous (aq) and MI 0.2% aq. Results: Three hundred five patients (6.3%) had a positive reaction to MCI/MI; this is a significant increase from the previous cycle (5.0%, 2011Y2012; P = 0.011). Five hundred twenty-one patients (10.7%) had a positive reaction to MI. These 2 isothiazolinones were among the most common preservative allergens in the 2013 to 2014 cycle; 11.9% of patchtested individuals were allergic to 1 or both isothiazolinones. Individuals with MCI/MI and MI allergy were significantly more likely to have occupationally related skin disease (P G 0.0001) and hand dermatitis (P G 0.0001, P = 0.0474). Conclusions: The epidemic of isothiazolinone sensitivity documented in Europe is now in North America. Patch testing with only MCI/MI 0.01% aq will miss approximately half of isothiazolinone allergy cases, whereas testing with only MI 0.2% aq will miss approximately 10% of isothiazolinone allergy cases.

Original languageEnglish (US)
Pages (from-to)204-209
Number of pages6
Issue number3
StatePublished - Jun 1 2017

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Dermatology


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