Several papers concerning isothiazolinone preservatives were published in the September 2017 edition of the journal Contact Dermatitis. Abstracts were not made publicly available, but I’ve kindly been sent the full text of one – The importance of a complete declaration of isothiazolinones in products beyond cosmetics – by its lead author, Dr Anna Andersson.
It is a Danish paper, and it describes the case of a 9-year-old boy who was non-atopic (i.e. no history of allergy), and who developed eczema on his face, chest, arms and legs after his bedroom had been painted with an emulsion containing benzisothiazolinone (BIT) and the MCI / MI mix. You can guess what the diagnosis eventually turned out to be.
The discussion points to the difficulty of diagnosing allergic contact dermatitis (ACD) to MI in children. “As exposure may be airborne,” say the writers, “there is no obvious physical contact with the allergen and the association is therefore easily overlooked.”
They add that symptoms of airborne ACD look very similar to some other types of dermatitis: “This is a recurring observation in all published case reports, resulting in delayed diagnosis, delayed treatment, and, most importantly, delayed removal of exposure.”
In Europe, MI is found in 93% of paints and BIT in 96%. Very few are free of isothiazolinones (see our listing here for some suggestions), but those that aren’t safe may not be labelled as isothiazolinone-containing.
Labelling rules are far less strict for chemical products than they are for cosmetics, but some ingredients have to be declared when present at certain levels.
For instance, in the EU, BIT has to be declared both as an ingredient and potential sensitiser when present at 0.05% or over and declared as an ingredient when present at 0.005% or over.
Similarly, the MCI / MI mix has set limits, at 0.0015% and 0.00015%.
No ‘bespoke’ limits have been set for MI when used alone, meaning it only has to be declared when present at far higher levels – unbelievably these are 1% and 0.1%, which are both extremely high, and effectively means that MI is rarely declared when present, as it is rarely used at such extreme concentrations.
The Good News …
The European Chemicals Agency have proposed reducing this too-high limit for MI from 1% and 0.1% to 0.0015% and 0.00015% respectively. Given that MI is ineffective below 0.005% it means that MI will have to be declared on paints – probably by the end of 2018 – as a potentially sensitising allergen and ingredient. But will it survive this move? Will legislators ban it? Will paint manufacturers turn to other preservatives instead?
It’s hard to predict.
Potentially, though, this could be another small positive step for those with isothiazolinone allergies.
The 9-year-old lad was quickly diagnosed partly because his father was a chemist, and recognised that the MCI and BIT on the paint’s labels were potential allergens. Most other parents might not.
In conclusion, some final words from the researchers: “This case illustrates the importance of a complete declaration of all isothiazolinones, including MI, in non-cosmetic and industrial products. We recommend that full ingredient labelling is introduced for such products, as is the case for cosmetics.”
Legislators have sometimes taken too long in the past to heed warnings about the isothiazolinones coming from dermatologists and other experts.
Let’s hope they don’t wait too long to heed this one.