This is a non-exhaustive collection of research papers into or involving MI / MCI or other isothiazolinones, and other related news about methylisothiazolinone and its chemical relatives.


October 2023 — via Journal of the American Academy of Dermatology
Intriguing research revealing a number of important points, including that patch-testing solely for MI / MCI can miss a large proportion of reactivity to BIT. 

April 2023 — via Contact Dermatitis
Study finding a more recent upturn (following a previous decrease) of occupational MI / MCI allergy. 

March 2023 — via JAMA Dermatology
Trends in the Prevalence of Methylchloroisothiazolinone/Methylisothiazolinone Contact Allergy in North America and Europe



September 2022 — via Contact Dermatitis
Tattoo inks on the EU market should not contain greater than 10mg/kg of isothiazolinone preservatives, but this Italian study shows that many are still non compliant. 

August 2022 — via Dermatitis
Allergic Contact Dermatitis of the scalp is associated with products applied to the scalp: 6% of cases implicate MI / MCI. 



September 2021 — via Contact Dermatitis
Benzisothiazolinone is beginning to overtake both MI and MCI as the top isothiazolinone sensitiser in the UK (likely down to greater restrictions on MI / MCI in cosmetics following EU legislation).

August 2021 — via Contact Dermatitis
Contact allergy to MI in Belgium has dipped to pre-epidemic levels, thanks to EU regulation, but BIT (benzisothiazolinone) remains of concern. 

July 2021 — via Contact Dermatitis
“Male painters with occupational dermatitis (OD) have a significantly higher rate of allergic contact dermatitis and face dermatitis than male patients with OD who work in other professions. Positive patch tests to epoxy resin, methylisothiazolinone (MI), and methylchloroisothiazolinone (MCI)/MI were significantly more frequent in painters with OD than in the other groups.”

February 2021 — via Dermatitis
Isothiazolinones common in children’s toy slime, with over 70% of products tested found to contain them. See also an earlier blog post here

February 2021 — via The Journal of the American Academy of Dermatitis
1 in 8 North American patch tests 1994–2016 were positive for an isothiazolinone preservative. (NB. This is around 12%, but refers to those patients referred for patch testing, NOT — as is often assumed in the isothiazolinonp-allergic community — to the general population. 



December 2020 — Via Dermatitis
The use of isothiazolinone test kits designed for cooling water treatments are not suitable for testing household detergents and personal care products, contrary to some reports purportedly suggesting otherwise. See blog here

December 2020 — Via Journal of the American Academy of Dermatology
A retrospective study of hand dermatitis cases (2000–2016) has found MI to be in the top 5 of the most clinically significant allergens. 

November 2020 — via Dermatitis
Patients primarily and strongly sensitised to MI may also react to OIT, but far less likely to BIT. 

October 2020 — via Dermatitis
Another study suggesting that isothiazolinones in laundry detergents do not persist in clothing materials after machine washing — but may in hand washing due to insufficient rinsing. 

February 2020 — via Contact Dermatitis
A German paper adding to the growing perspective that it is through paint exposure which is increasingly posing the greatest risk, especially to painters. 

January 2020 — via Dermatitis
Three isothiazolinone preservatives among the top 10 allergens identified in US laundry products. 



13th September 2019 — via Contact Dermatitis
Another paper looking at the reduction of isothiazolinone allergy cases in Europe following their banning in leave-on cosmetics, focusing on Spain.

9th September 2019 — via Environmental Toxicology
Worrying paper calling for further studies into lung injury caused by isothiazolinones in detergents / disinfectants used in humidifiers / air conditioning, which are the subject of a growing scandal in Korea.

September 2019 — via Pediatric Allergy and Immunology
This is a very interesting looking abstract of a paper which calls for age specific patch testing series for children, adolescents and adults … not only for the isothiazolinones, of course, but these are explicitly mentioned.

August 2019 — via Journal of the European Academy of Dermatology and Venereology
Research following up on changing scale of MI allergy in Europe following legislative restrictions on its use in cosmetics, has found that there has been a significant 50% decrease between 2015 and 2017 in MI allergy diagnoses among patch tested individuals. Changing source of exposure means it’s going to be occupational and household detergent exposures increasingly responsible, with cosmetics featuring less.

August 2019 — via Contact Dermatitis
Study looking at changes in contact allergens in Thailand between 2006 and 2018. It may not be a surprise to learn that “Methylchloroisothiazolinone (MCI)/MI was the only allergen associated with a significant increase of positive reactions, from 2.4% to 10.7%”.

May 2019 — via Contact Dermatitis
Small study assessing cases of relapse following diagnosis of MI allergy. Two thirds of patients experience relapse of symptoms, with the average period five months, and for one in five it is severe. Rinse-off cosmetics mainly to blame, perhaps surprisingly, though to be expected were the key sites of relapse — the hands and the face. “The main difficulties encountered in the avoidance strategy were hidden sources of MI, the lack of labelling on industrial products, the complexity of cosmetic labelling, and remembering the name of the allergen”.

April 2019 — via Journal of Cosmetic Dermatology
Preservatives, among which methylisothiazolinone, shown to inhibit the survival of beneficial skin bacteria. MI was one of the two worst offenders in this regard. 

January 2019 — via Contact Dermatitis
Thai researchers find that the previous banning of MI / MCI in leave-on products — despite the lack of full compliance and enforcement — has resulted in drastic reduction of cases of MI / MCI and MI allergy among referrals and patients to their clinic. 

January 2019 — via META Magazine
Paper products in the EU whose manufacturers wish to bear the EUEcoLabel will have to start phasing out the use of a number of chemical ingredients — methylisothiazolinone — and full compliance will be a requirement by mid-2020.

January 2019 — via The Journal of Allergy and Clinical Immunology in Practice
A paper looking at patch testing in the UK, which found that almost 6% of those tested at a dermatology clinic tested positive for MI. The recommendation is for more patch testing to take place, but the UK has a long history of under-resourced allergy services. 

January 2019 — via Drug and Chemical Toxicology
Deeply unpleasant case: the first of acute respiratory distress syndrome and alimentary bleeding caused by inhalation of humidifier disinfectant. 



December 2018 — via Journal of Cosmetic Dermatology
Interesting study looking at the effect of cosmetic preservatives on beneficial skin bacteria. Methylisothiazolinone among the worst of five. 

October 2018 — via Contact Dermatitis
In a systematic meta-analysis, Prevalence of contact allergy in the general population, contact allergy shown to effect 1 in 5 people, with MI / MCI effecting 1.5% of the general population. 

October 2018 — via Journal of the European Academy of Dermatology and Venereology
Isothiazolinone derivatives and ACD: a review. “Despite a decreasing prevalence of allergic contact dermatitis from MCI/MI and MI, cases caused by occupational exposure and non-cosmetic isothiazolinone sources are on the rise. Moreover, sensitization to newer and lesser known isothiazolinones has been reported.” 

21st September 2018 — via Clinical and Experimental Dermatology
MI one of the many common contact allergens found in baby cosmetic products. 

25th July 2018 — via The International Journal of Food Microbiology
Worrying paper published claiming isothiazolinone mix (MI / MCI) is a viable alternative to chlorine in food processing. 

8th June 2018 — via Contact Dermatitis
Another paper confirming high prevalence of MI allergy in France, focusing on eyelid patch testing. Over 10% of those tested reacted. 

28th February 2018 — via Dermatitis
The Role of Cleaning Products in Epidemic Allergic Contact Dermatitis to Methylchloroisothiazolinone / Methylisothiazolinone: abstract seems to be suggesting those working in the cleaning profession are more likely to develop isothiazolinone allergies. 

26th February 2018 — via Contact Dermatitis
Facial dermatitis caused by undeclared methylisothiazolinone in a gel mask: is the preservation of raw materials in cosmetics a cause of concern? This is an important question for scientists and cosmetic formulators to be asking: are the preservatives used in cosmetics’ raw ingredients being ‘carried over’ onto the label of the finished product — or not? And how can we know ‘hidden’ MI or MCI isn’t therefore an issue? 

5th January 2018 — via Clinical and Translational Allergy
Controversial paper — MI contained in detergents is not detectable in machine-washed textiles — and therefore MI-containing laundry detergents are “safe” for the consumer if used according to machine instructions, say the researchers. For our article on this subject, including comments from one of the researchers, click here



25th December 2017 — via Food and Chemical Toxicology
A Quantitative Risk Assessment research paper which found that “The restricted use of MI in PCPs does not seem very effective in lowering the risk on skin sensitisation”. But see also this very good point made by MI advocate Jan Hoverman Stanley in comments. 

19th December 2017 — via Contact Dermatitis
Follow-on study on paints sold in European market find no decrease in isothiazolinone preservative use in last 2 or 3 years. Still, the vast majority contain one or more. 

12th December 2017 — via Contact Dermatitis
Results of a small piece of research into photo-aggravated contact dermatitis to MI / MCI.

12th December 2017 — via Trading Standards Scotland
Multiple examples of MI-containing leave-on cosmetics found for sale throughout Scotland. 

7th November 2017 — via Environmental Toxicology
MI may induce cell death and inflammatory response through DNA damage in human liver epithelium cells.

November 2017 — via European Commission
Reports coming in of various leave-on products on the European markets (assorted countries) illegally containing MI or MI / MCI. See our summary reports here and here

15th September 2017 — via the European Association of Dermatology and Venereology
Dermatologists support and call for greater transparency and restriction on the use of isothiazolinones in products. 

19th June 2017 — via Journal of the European Academy of Dermatology and Venereology
Retrospective analysis of 30,000+ patch tests across Europe from 2013/2014 shows 20% MI allergy in some parts of the continent. 

24th May 2017 — via Dermatitis
Epidemic of Isothiazolinone Allergy in North America: Prevalence Data From the North American Contact Dermatitis Group, 2013-2014. Now almost 12% of patch tested individuals.

24th May 2017 — via Dermatitis
Confirmation that testing with MCI / MI at 0.02% is considerably more efficient at diagnosing that at 0.01% (with no worse adverse reactions in patients).

28th April 2017 — via PLOS ONE
Detrimental effects found in children’s airway function due to exposure to MI / MCI in humidifier disinfectant. 

28th February 2017 — via Cosmetics Design Europe
Very useful article — COSMED provides international overview of methylisothiazolinone. 



28th December 2016 — via Contact Dermatitis
“The use of methylisothiazolinone (MI) in cosmetic products has caused an unprecedented epidemic of MI contact allergy.” 6% of Europeans tested at dermatology clinics have MI allergy. 

20th December 2016 — via Dermatitis
“Wet wipes are an important source of contact allergy. Preservatives are the main allergens, especially isothiazolinones.”

29th November 2016 — via PubMed / JEADV
Data collected by the European Surveillance System on Contact Allergies (ESSCA) network between 2009 and 2012 reveal that MI (4.5%) and MI/MCI (4.1%) were the most prevalent positive patch testing biocide allergens.

7th October 2016 — via PubMed / Contact Dermatitis
Many papers published on methylisothiazolinone (and other isothiazolinone) allergies in the journal, Contact Dermatitis, November 2016 edition. Some of the most notable, summarised by us here, include exposure via trousers and spectacle frames. 

31st August 2016 — via British Journal of Dermatology
New letter: has the epidemic of allergic contact dermatitis due to methylisothiazolinone reached its peak? (See also our analysis here.) 

19th August 2016 — via Contact Dermatitis
Leather treated with an isothiazolinone — in this case, octylisothiazolinone — can trigger contact dermatitis and may sensitise, with potential for cross-reactivity with methylisothiazolinone. 

22nd July 2016 — via EUR-Lex
Amending Annex V to Regulation (EC) No. 1223/2009 re: MI in leave-on products, with full ban to be effective from 12th February 2017. (See also our blog here.)

25th June 2016 — via PubMed
Study confirming cross-reactivity between methylisothiazolinone, octylisothiazolinone and benzisothiazolinone. 

3rd May 2016 — via PubMed
Contact allergies to MI / MCI, formaldehyde and fragrance allergies are significantly associated, according to this Swedish study. 

1st April 2016 — via European Commission
The EC has opened a consultation on methylisothiazolinone (MI) in the framework of Regulation (EC) No. 1223/2009 — rinse-off cosmetic products. Interested parties are invited to submit comments on the proposal (outlined here), to restrict use of MI to 15ppm in rinse-off products, while demanding a ‘contains MI’ labelling message, and to ban it in leave-on hair products. Deadline for submission of comments is 1st July 2016.

19th March 2016 — via PubMed
Abstract of a new study determining the prevalence of MI and MCI allergy in Italian populations — although the figures look to be drawn from those who underwent patch testing NOT the general population. Nevertheless, figures are high, and counter the prevailing view that methylisothiazolinone allergy in Italy and other south European countries was not a serious problem. It is. 

4th March 2016 — via Health Canada
L’Oreal Paris Canada have recalled their Ideal Moisture Dry and Sensitive Day Cream due to possible raised levels of MI in some product samples. Read our blog here for more information. 

14th January 2016 — via PubMed
MI / MCI named as one of the top ten allergens among children suspected of having allergic contact dermatitis, for one third of whom a PEAS (Pre-Emptive Avoidance Strategy) might be worth recommending. 

11th January 2016 — via PubMed
Opinion of the Scientific Committee on Consumer safety (SCCS) on the safety of the use of Methylisothiazolinone (MI) in cosmetic products (sensitisation only).

The EU’s SCCS has reviewed the evidence on the safety of MI as a potential sensitiser in cosmetics, and concluded it is not safe in rinse-off products at a concentration of 100ppm (0.01%) or even 50ppm (0.005%), nor at a level of 100ppm for leave-in hair cosmetic products. For rinse-off cosmetic products, a concentration of 15 ppm (0.0015%) MI is considered safe from the point of view of sensitisation (i.e. it should not sensitise a non-allergic individual to MI) — but of course is not safe for someone already sensitised.
Essentially, the recommendation here is to limit its use to no greater than 0.0015% — which may be too low to be effective.

1st January 2016 — via PubMed
MI should be added to routine patch tests for contact dermatitis in order to identify cases missed from testing only MCI/MI.  



28th December 2015 — via Premium Beauty News
Canada adds new restrictions to the use of MI/MCI. 

4th November 2015 — via JAMA Dermatology
New published study, recommending that patch testing for MI as well as MI/MCI be undertaken in suspected cases of contact dermatitis to an allergen. “Recent regulations by the European Commission have banned MCI-MI in all leave-on body products as of July 16, 2015” it concludes.
(Ed’s note: New products containing MI/MCI blend which are leave-on can no longer be put on the market after this date, but shelves must be cleared of such products and all others from 16th April 2016. Be aware too that leave-on products containing only MI are still permitted beyond this date)

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