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Legal levels of common preservative are ‘not safe for consumers’

Legal limits of a preservative causing an epidemic of skin allergy are not safe for use in everyday products, according to new research in the British Journal of Dermatology.

Methylisothiazolinone (MI) is a preservative that is widely used in cosmetics, toiletries and other household items including paints. At present, the maximum concentration at which it is allowed to be used in cosmetics, known as the ‘permitted usage’, is 100 parts per million (100ppm, or 0.01%), both in ‘leave on’ products which are designed to remain on the skin (such as moisturisers and sunscreens) or ‘rinse off’ products which are washed off (such as liquid hand soap, shampoo and shower gel).

Allergic reactions to skin contact with MI have increased by 93 per cent in just three years*, prompting warnings from dermatologists across Europe and a public outcry at a failure to ban the chemical from everyday consumer products.

Studies have found that MI used at the permitted level in leave-on products is what is most likely to have caused the epidemic of MI allergy. This study, which will appear in the July edition of the journal, examines reactions to MI from rinse-off products, and whether individuals already allergic to MI will react to levels that are permitted in rinse-off products.

The study tested rinse-off liquid hand soaps, containing two permitted concentrations of MI, on 19 people with a MI allergy, to see if these concentrations have the potential to trigger allergic contact dermatitis (eczema caused by allergy). 10 of these people received a soap containing 100 ppm MI, and nine received half that concentration, 50 ppm. 19 people with no MI allergy, acting as a control group, also used the products. The soaps were applied to test areas of skin five times a day for up to 21 days, and rinsed off shortly after application, as would be usual with soap use.

All of the test subjects with an MI allergy had reactions to the rinse-off product containing 100 ppm MI. When reducing the concentration to 50 ppm, 78 per cent (7 out of the 9) MI-allergic subjects reacted. None of the control group suffered a reaction, and none of the MI patients suffered a reaction to a control product that did not contain MI.

Given the widespread rates of MI allergy in the general population, with MI allergy affecting at least 11 per cent of people attending UK patch test clinics, the authors conclude: “Rinse-off products preserved with 50 ppm MI or more are not safe for consumers. No safe level has yet been identified.”

This latest research coincides with an editorial written by the Executive Committee of the European Society of Contact Dermatitis in next month’s edition of the journal Contact Dermatitis1, in which the group outlines how the European Commission has ignored the recommendations of its own Scientific Committee on Consumer Safety (SCCS), which in 2013 advised that MI should be banned from all leave-on cosmetic products, and that the legal limit in rinse-off products should be reduced to 15 parts per million (15 ppm) instead of the current 100 ppm.

Nina Goad of the British Association of Dermatologists said: “It has been two years since dermatologists first warned the public about a contact allergy epidemic in the UK stemming from the use of MI in cosmetic products. We now know it is a problem in many other products also, such as paints and detergents, as well as in the workplace. The epidemic shows no sign of waning, and is unlikely to do so without action on a legislative level.”

Dr David Orton, President of the British Society of Cutaneous Allergy and Secretary of the European Society of Contact Dermatitis, said: “Dermatologists from the UK and indeed many other parts of Europe have been vocal over the past two years about the unprecedented rise in allergy to MI and the many sources of exposure to this widely used preservative. As far back as 2013, the European regulatory body was advised by their own safety committee (the SCCS) and also by Cosmetics Europe who represent the major European cosmetic manufacturers, on what should be done.

“Cosmetic Europe’s advice to their members stressed that action should not be dependent upon regulatory intervention – yet it seems to have fallen on deaf ears. We continue to see unacceptable levels of allergy and patients, both adults and children, experiencing debilitating allergic responses. There has been no expedient action taken either by regulators or the manufacturers – UK and other European citizens’ health continues to be put at risk. One can only wonder what it takes for these bodies to act. Many manufacturers have cynically let stocks of their products remain on the shelves whilst they are busy re-formulating behind the scenes. In my view, consumers need to be made aware of these failures of regulation and the inertia of the manufacturers.”

Ben Smith’s two-year-old son, Tennyson, was recently diagnosed with MI allergy, believed to have been triggered by use of baby wipes. He said: “To find out that the allergy was actually caused by the use of this chemical in baby products was very upsetting. What made it even more shocking is to learn that the problem was known by the manufacturers because they had already been notified and lobbied yet they chose to continue to include the chemicals and not warn parents.

“Having the allergy has caused lots of upset and confusion over the last 14 months. My son has suffered severe itching and painful inflammations during multiple flare-ups lasting approximately five days each. These always mean very disturbed sleep with crying in the night, which had a knock-on effect on daily life.

“Whenever your child is upset, the immediate reaction is to find a way to soothe them and fix whatever the situation is. Not knowing what the allergy was and how to avoid it permanently lead to many feelings of guilt and upset. I am thankful that we got through it and now know what the allergy is to, and we have the ability to isolate and avoid it. However, I am very angry that this is something that could have been avoided from the start and am keen to help ensure that other children and parents do not suffer from it.”

MI is widely used, either on its own or in combination with methylchloroisothiazolinone (MCI), as a preservative in personal care products such as moist tissue wipes, cleansers, shower gels, deodorants and shaving foam, as well as in everyday professional and household products such as detergents, paints and glues.

In December 2013, in response to pressure from dermatologists, Cosmetics Europe, the European cosmetics trade association, recommended to all its members that MI should be immediately removed from all leave-on skin products and personal care products, including cosmetic wet wipes, without waiting for action from regulators. In practice, however, many leave on cosmetic products containing MI have remained on the shelves. Furthermore, safe levels of MI in rinse-off cosmetics have not yet been determined, either for induction of allergy in the first place, or for elicitation of responses such as eczema in people who are already allergic, yet industry continues to use it at levels of up to 100ppm.

Prior to 2005, MI had to be mixed with MCI and was generally found in concentrations of around four parts per million (ppm) in personal care products. However, from 2005 MI was permitted for use on its own in far higher concentrations - up to 100 ppm – which is a 25-fold increase on the previous levels of the preservative and widely thought to be responsible for the disease increase. MI/MCI mix has been banned from leave-on products and reduced in rinse-off products but this has not been the case for use of MI on its own, despite the recent increase in MI allergy being largely attributed to its use in higher concentrations without the addition of MCI.

Dermatologists have also raised concerns that for non-cosmetic products, there is no legal requirement to show the presence of MI on product labelling, and there is no restriction on what concentration it can be used at. Last year, doctors from University Hospital Lewisham and St John’s Institute of Dermatology identified MI in paint as a serious potential public health concern. Exposure to paints with MI can trigger reactions in those already sensitised to the allergen, as well as causing those with no history of allergy to MI to react.2

At the same time, scientists from the Leeds, Manchester and Bath warned that MI can be an occupational health risk, after treating workers who developed MI reactions in the course of their employment due to use of industrial products including glue.2

The British Association of Dermatologists has endorsed the opinion of the SCCS and called on EU Regulators to:
• Ban MI in all leave-on cosmetic products / toiletries
• Reduced the permitted level of MI to 15 ppm in rinse-off products
• Classify MI as an allergen according to CLP Regulation (Classification, Labelling and Packaging of substances and mixtures), to ensure it is listed as an ingredient in non cosmetic / household detergent products, to allow the public to identify its use within these products.


Notes to editors:

For more information please contact the media team:, 0207 391 6094. Website: Case studies available on request.

If using this information, please ensure you mention that the study is being released in the British Journal of Dermatology, the official publication of the British Association of Dermatologists. Study details: British Journal of Dermatology: Methylisothiazolinone in rinse-off products causes allergic contact dermatitis: a Repeated Open Application study; K. Yazar, M.D. Lundov, A. Faurschou, M. Matura, A. Boman, J.D. Johansen and C. Lidén; DOI: 10.1111/bjd.13751. Articles in the BJD can be viewed online:


*UK data shows a rise in MI allergy among patch tested individuals at 11.1%:
Data from Europe and elsewhere also shows prevalence as high as 10%: e.g.

1 Contact Dermatitis (/journal/10.1111/(ISSN)1600-0536) Volume 72, Issue 6 (/doi/10.1111/cod.2015.72.issue-6/issuetoc), Article first published online: 11 MAY 2015


About us:
The British Association of Dermatologists is the central association of practising UK dermatologists. Our aim is to continually improve the treatment and understanding of skin disease. For further information about the charity, visit

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