Contact allergy caused by isothiazolinone derivatives: an overview of non-cosmetic and unusual cosmetic sources

Abstract

The isothiazolinone derivatives, methylchloroisothiazolinone (MCI), methylisothiazolinone (MI), benzisothiazolinone (BIT), and octylisothiazolinone (OIT), owing to their strong bactericide, fungicide and algicide properties, are widely used in non-cosmetic products, such as chemical (industrial) products, household detergents, and water-based paints, and the former two derivatives are also used in cosmetic products. However, given their inherent sensitization potential (with MCI > MI > BIT > OIT), allergic contact dermatitis is frequently observed, both in consumers as well as workers in various industries. In this review, we provide an update on the use of MCI/MI and MI in cosmetics, highlighting certain aspects of MI; the use of excessive concentrations, the presence in some less familiar cosmetic products, and the association with unusual clinical manifestations. Furthermore, the use of isothiazolinones in dishwashing and washing-machine liquids, cleaning agents for dental care, and their general presence in multi-purpose household detergents, which may elicit (airborne) allergic contact dermatitis, is discussed. Finally, we provide a brief overview of the use of isothiazolinone derivatives in the paint and textile industry, and of OIT in the leather industry in particular.

Photoaggravated allergic contact dermatitis and transient photosensitivity caused by methylisothiazolinone

“…Atypical clinical presentations caused by sensitization to MCI/MI and MI have been reported , and potential photoaggravation was first reported in 2014 . Pirmez et al.…”

Isothiazolinone derivatives and allergic contact dermatitis: a review and update

“…According to LLNA data, isothiazolinones are classified in order of sensitization risk: MCI > MI > OIT > BIT . This classification seems more accurate than the more frequently cited one, namely MCI > MI > BIT > OIT, with the difference likely explained by the higher frequency of use and higher exposure to BIT . Potential MCI/MI contaminants, such as 4,5 dichloromethylisothiazolinone (DCMIT), have historically contributed to its tendency to cause skin sensitization, considered less common with today's enhanced purity levels…”

“…Other potential allergen sources were highlighted, including mouthwashes, toilet fresheners, fuels and animal cosmetics …”

“…Lastly, isothiazolinones are likely to be present in imported cosmetic products (e.g. BIT in sunscreen products from the United States or Canada) . Indeed, the legislation may vary across geographical regions.…”

“…In the event of accidental chemical burns with industrial products containing high MCI/MI or MI concentrations, it has been advised to rinse thoroughly with water (dilution effect) or use sodium bisulphite that deactivates MCI/MI . Concerning paints, isothiazolinone‐free water‐based paints are available, though hard to find in daily practice . Chemical deactivation procedures have also been reported, such as paint alkalinization, to obtain a pH of around 10–11.…”