It’s an ‘epidemic’ of contact dermatitis

One in 10 people tested may be allergic to a common cosmetic preservative, with a growing number of everyday products causing issues.

Cosmetics, epoxy resins and essential oils are key contributors to the surge of allergic contact dermatitis cases, delegates were told at the Dermatology Days of Paris conference at the end of last year. 

Professor Angele Soria, a French dermatologist, first put isothiazolinones – specifically methylisothiazolinone (MI), a preservative found in a variety of cosmetic products – under the microscope.  

“About 10% of the population that we tested showed allergies to these preservatives,” Professor Soria said, according to recent Medscape reporting.  

The preservatives became a lot more common about 15 years ago after parabens were found to be endocrine disruptors, leading to a boom in allergic contact dermatitis diagnoses across Europe. The use of MI in leave-on cosmetics was banned in Europe in 2015 as a result. 

MI can also be found in certain water-based paints, household cleaning products, leather-preserving fungicides, florists’ gel cubes for preserving flowers and children’s toys. 

“We are therefore surrounded by these preservatives, which are no longer only in cosmetics,” said Professor Soria, head of the allergology unit at Tenon Hospital in Paris.  

Epoxy resins are another allergen that was becoming more common, especially in recreational activities, she warned. In the past, exposure to epoxy resin was limited to certain professions, but there were a growing number of cases where these materials were found in arts and crafts.  

“The growing popularity and online availability of epoxy resins means that allergic reactions should now be considered even in nonprofessional contexts,” Professor Soria said.   

(Meth)acrylates, another compound found in cosmetics, were also a growing concern. 

“We are currently witnessing an epidemic of contact dermatitis in the general population, mainly due to nail cosmetics, such as semipermanent nail polishes and at-home false nail kits,” Professor Soria said. 

These allergens, which are sensitising when they come into contact with the skin, now come with labels in the EU warning of the dangers of these products.    

Finally, Professor Soria flagged that essential oils were not as risk-free as their “natural” labels may suggest. Many essential oils contained fragrant molecules such as terpenes, which had the potential to become highly allergenic after repeated topical, oral or inhalation exposure.   

Professor Soria recommended corticosteroid creams as the first line of treatment where dermatologists and other healthcare professionals suspect allergic contact dermatitis, followed by a detailed patient interview and patch testing to identify and confirm specific allergens.