Biocide Allergy: The MI Epidemic, Its BIT Successor, and Formaldehyde Releasers
Biocide contact allergy — particularly to methylisothiazolinone (MI) and its successor benzisothiazolinone (BIT) — represents one of the most significant contact allergy epidemics of the 21st century. MI sensitization peaked at 15.0% in NACDG 2017-18 after consumer flight from parabens drove its widespread adoption. EU bans have reduced European rates; US rates remain high at 11.5%. BIT is emerging as the next epidemic at 10.4% (NACDG 2019-20). Formaldehyde releasers remain significant allergens.
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Key facts
Methylisothiazolinone sensitization peaked at 15.0 percent in NACDG 2017–18 patch test data — among the highest rates ever recorded for any contact allergen.
Benzisothiazolinone (BIT) sensitization has risen from less than 0.3 percent in 2014 to 10.4 percent in NACDG 2019–20, mirroring the early MI epidemic trajectory.
Standard MCI/MI patch testing at 100 ppm misses approximately 40 percent of MI-only allergies; separate MI testing at 0.2 percent aqueous is required for complete evaluation.
Parabens, which were replaced by MI under consumer pressure, have sensitization rates of approximately 1 percent — 15 times lower than the peak MI rate.
The EU banned MI from leave-on cosmetics in 2017; US rates remain high at 11.5 percent because no equivalent federal restriction exists.
What Are Biocides and Why Do They Cause Contact Allergy?
Biocides are chemicals that kill or suppress microorganisms — bacteria, molds, and yeasts — to preserve products from spoilage and contamination.
In cosmetics, personal care products, and household cleaning formulations, biocides function as preservatives, extending shelf life and preventing potentially dangerous microbial contamination in water-containing products. The need for preservation is genuine: water-based products without any preservatives can harbor bacteria and fungi that cause skin infections and product degradation.
The central challenge in cosmetic and industrial preservation is the 'preservative dilemma': the same chemical properties that make biocides effective antimicrobials — reactivity with microbial proteins and cell membranes — also create potential for skin protein reactivity and immune sensitization. The more potent the antimicrobial, the higher the sensitization risk.
This page covers the most clinically important biocide contact allergens: the isothiazolinones (methylisothiazolinone/MI, methylchloroisothiazolinone/MCI, and benzisothiazolinone/BIT) and the formaldehyde releasers (quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, and bronopol). These are among the most prevalent contact allergens in current patch test practice — not rare theoretical concerns but major drivers of population-level sensitization.
Symptoms of MI, BIT, and Formaldehyde Releaser Contact Allergy
Recognizing symptoms early helps you get the right treatment faster.
Facial eczema (cosmetic exposure)
moderatePruritic erythema, scaling, and vesiculation on the face from MI in moisturizers, sunscreens, or facial cleaners — often initially attributed to a new product.
Eyelid dermatitis
moderateThin eyelid skin is highly susceptible to MI and formaldehyde releaser contact allergy; presents as swollen, red, scaly, intensely itchy eyelids.
Scalp and hairline dermatitis
moderateEczematous reaction at the hairline, behind the ears, and on the neck from MI-preserved shampoos and conditioners.
Hand and occupational dermatitis
moderatePainters and wet workers develop hand and forearm eczema from repeated MI exposure in water-based paints and industrial cleaners.
Fabric contact pattern eczema
moderateMI residue in laundered clothing causes eczema at fabric contact sites — trunk, inner thighs, axillae — mimicking other conditions and typically delayed 24–72 hours after wearing freshly laundered clothes.
Airborne contact dermatitis (painters)
moderateAerosolized MI from water-based paints deposits on facial and eyelid skin of painters, producing airborne contact dermatitis in areas not directly touching painted surfaces.
Widespread generalized dermatitis
severeSeverely sensitized individuals using multiple MI-containing products daily may develop widespread eczema across the body, which can be debilitating and difficult to connect to a single cause without patch testing.
When to see a doctor
Contact allergy to biocide preservatives presents as allergic contact dermatitis — a pruritic, eczematous reaction at sites of allergen contact. The distribution reflects exposure patterns: cosmetic MI allergy typically affects the face (from moisturizers), scalp and hairline (from shampoos), or body (from body lotions). Industrial MI exposure from paints causes hand and forearm eczema in painters. Formaldehyde releaser allergy follows product use patterns — face, neck, hands, or clothing contact sites. A critical diagnostic challenge is the 'fabric contact pattern': when MI-preserved laundry products leave residues in clothing, eczema may appear at truncal clothing contact sites — a pattern easily misattributed to food allergy, internal disease, or other causes. Recognizing the fabric contact distribution and testing the laundry product hypothesis is essential. Airborne MI exposure in painting environments can produce facial and eyelid eczema from aerosol deposition — a pattern resembling photodermatitis or inhalant allergy. Seek medical attention for any widespread or rapidly spreading eczematous reaction, or if facial swelling accompanies skin symptoms.
Biocides and Respiratory Effects
Isothiazolinone biocides (MI, BIT) are not established causes of IgE-mediated allergic asthma. Their primary health impact is through cutaneous sensitization and contact dermatitis. However, occupational inhalation of MI-containing paints, coatings, or cleaning products at high concentrations has been associated with respiratory irritation and — in a small number of reported cases — occupational asthma through a non-classical mechanism. This is distinct from the well-characterized skin sensitization pathway. Formaldehyde, released by formaldehyde-releasers, is both a contact allergen and a respiratory irritant. Formaldehyde inhalation at occupational concentrations causes nasal and bronchial irritation and has been associated with occupational rhinitis in pathology and anatomy laboratory workers, funeral home staff, and those working in formaldehyde-rich manufacturing environments. Individuals with pre-existing asthma should minimize occupational formaldehyde exposure.
Complications of Biocide Contact Allergy
MI and formaldehyde releaser contact allergy has significant lifestyle impacts because these preservatives appear in so many product categories. A patient sensitized to MI must potentially replace their moisturizer, sunscreen, shampoo, body wash, household cleaners, laundry detergent, wipes, and workplace products simultaneously. The burden of vigilant label reading and product replacement is substantial. The MCI/MI patch testing gap creates a diagnostic complication: standard patch testing with MCI/MI (Kathon CG) at 100 ppm aqueous misses approximately 40% of MI-only allergies. Patients tested only with MCI/MI who are negative may still be MI-sensitized — separate MI testing at 0.2% aqueous is essential for complete evaluation. Many patients are inadequately diagnosed due to this testing limitation. BIT sensitization expanding to 10.4% in NACDG 2019-20 parallels early MI trajectory, suggesting we may be in the early stages of a new epidemic — particularly concerning given that BIT is replacing MI in many industrial and household products following EU restrictions.
Broad product cross-reactivity and lifestyle burden
MI sensitization requires vigilant avoidance across dozens of product categories; the cumulative burden of label-reading and product replacement significantly affects quality of life.
Missed diagnosis from inadequate patch testing
MCI/MI testing at standard concentrations misses ~40% of MI-only allergies; patients may remain undiagnosed and continue using MI-containing products without understanding the cause of their dermatitis.
Formaldehyde releaser cross-reactivity
Patients sensitized to formaldehyde must also avoid all formaldehyde releasers (quaternium-15, DMDM hydantoin, etc.), which are present in many different product categories — expanding avoidance requirements substantially.
Occupational implications for painters and cleaners
Professional painters sensitized to MI in water-based paints face occupational accommodation challenges; switching to solvent-based or MI-free water-based paints may be required.
The MI Epidemic: How Consumer Behavior Created a Public Health Crisis
The methylisothiazolinone (MI) epidemic is a case study in how well-intentioned consumer behavior and incomplete safety data can collide to create widespread harm. In the early 2000s, consumer advocacy groups raised concerns about parabens in cosmetics — concerns largely based on misinterpreted science about estrogenic activity. Consumer demand for 'paraben-free' products surged, and cosmetic manufacturers sought replacement preservatives. MI was approved for use alone in leave-on cosmetics at 100 parts per million (ppm) around 2005, based on LLNA (Local Lymph Node Assay) data that significantly underestimated its sensitization potential in humans.
How it works
MI and MCI/BIT are electrophilic thiol-reactive chemicals that bind covalently with cysteine residues in skin proteins, forming hapten-protein conjugates. These conjugates are processed by Langerhans cells and dendritic cells in the epidermis, which migrate to regional lymph nodes and activate allergen-specific T lymphocytes — the sensitization phase of Type IV delayed hypersensitivity. On re-exposure, sensitized T cells recognize MI-protein conjugates and mount an inflammatory cascade producing eczematous dermatitis 24–72 hours after contact. Formaldehyde releasers sensitize through the same mechanism as formaldehyde itself — formaldehyde is released into the product matrix where it reacts with skin proteins to form immunogenic Schiff base adducts.
MI use surged in cosmetics, personal care products, and household cleaners throughout the late 2000s and early 2010s. The result was catastrophic from a sensitization standpoint: MI rates in patch test populations rose from negligible to a peak of 15.0% in NACDG 2017-18 and 9.39% in UK data by 2013. Critically, this occurred not because people are unusually reactive, but because MI is a genuinely potent sensitizer that was deployed at concentrations generating population-level sensitization.
BIT (benzisothiazolinone) is now following an eerily similar trajectory as a 'safer' replacement for MI in household and industrial products: ≤0.3% sensitization in 2014, rising to 5.0% in Danish data and 10.4% in NACDG 2019-20. The parallel with early MI is troubling.
Formaldehyde releasers — quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, and bronopol — work by slowly releasing low levels of formaldehyde into products. Formaldehyde is itself an IARC Group 1 carcinogen and a significant contact allergen (NACDG ~7.8% at 2% aqueous). Formaldehyde releasers carry their own sensitization rates: quaternium-15 is the most potent (7.7% NACDG; now banned in EU cosmetics), DMDM hydantoin ~2.8%, imidazolidinyl urea ~3%, diazolidinyl urea 2–4%, and bronopol ~3.3%.
Risk factors to watch for
Regular use of MI-containing cosmetics or personal care products
Daily application of leave-on products (moisturizers, sunscreens, body lotions) containing MI at concentrations up to 100 ppm generates sustained skin protein reactivity and progressive sensitization risk.
Wet work occupations
Healthcare workers, cleaners, caterers, and hairdressers who perform wet work have higher skin exposure to industrial preservatives including MI, BIT, and formaldehyde releasers.
Use of MI-preserved paints and building materials
Water-based paints, adhesives, and building products frequently contain high concentrations of MI as an in-can preservative — exposure during DIY painting and renovation is a significant non-cosmetic source.
Atopic skin barrier impairment
Compromised skin barrier allows greater penetration of MI and related biocides into the skin, increasing the concentration available for hapten-protein conjugation and sensitization.
Pre-existing formaldehyde sensitivity
Patients sensitized to formaldehyde are at risk of reactions from any formaldehyde-releasing preservative across all product categories — a single sensitization creates broad cross-reactivity.
The Allergy Cascade
Exposure
Allergen contact
Detection
Immune recognition
IgE Response
Antibody production
Mast Cells
Histamine release
Symptoms
Allergic reaction
1.Exposure
Allergen contact
2.Detection
Immune recognition
3.IgE Response
Antibody production
4.Mast Cells
Histamine release
5.Symptoms
Allergic reaction
Diagnosing Biocide Contact Allergy: The Testing Gaps Matter
Patch testing is the gold standard for diagnosing biocide contact allergy. For the isothiazolinones, the testing protocol requires attention to which agents are included: MCI/MI (Kathon CG, 3:1 ratio) is tested at 100 ppm aqueous in the standard NACDG and European Baseline Series — but this combination misses approximately 40% of MI-only allergies. Separate MI testing at 0.2% aqueous is essential and should be performed alongside MCI/MI to avoid false negatives. BIT is now being added to extended series in many centers given its rising prevalence. Formaldehyde is tested at 2% aqueous (NACDG rate ~7.8%); formaldehyde releasers (quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, bronopol) should also be tested individually. Patch testing typically takes 4–7 days: allergens applied on Day 0, removed at 48 hours, first reading at 48–72 hours, second reading at 96 hours. Late readings at Day 7 may be needed for metals but are generally not required for isothiazolinones. Product testing can supplement standard series: patients bring their suspect cosmetics and cleaners for ROAT (repeated open application test) or diluted patch testing when standard series do not capture the specific product preservative. At-home allergy testing services such as Curex offer comprehensive panels covering 40+ IgE-mediated allergens including environmental allergens, pet dander, and food allergens — useful for evaluating co-existing IgE-mediated conditions. However, biocide contact allergy is Type IV (not IgE-mediated) and requires patch testing by a dermatologist. The two testing modalities evaluate fundamentally different immune mechanisms.
MCI/MI patch testing (100 ppm aqueous)
Standard baseline series allergen for combined methylchloroisothiazolinone and methylisothiazolinone sensitization. Included in NACDG and European Baseline Series. Critical limitation: misses ~40% of MI-only allergies.
MI alone (0.2% aqueous)
Separate methylisothiazolinone testing essential for identifying MI-only sensitized patients who test negative on MCI/MI. Required for complete evaluation in suspected MI allergy.
Formaldehyde (2% aqueous) and formaldehyde releasers
Formaldehyde plus individual releasers (quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, bronopol) should be tested together. Positive formaldehyde result indicates avoidance of all releasers.
BIT (benzisothiazolinone)
Emerging allergen with 10.4% positivity (NACDG 2019-20); now being added to extended panels in many centers. Important for evaluation when standard MI testing is negative but household/industrial product exposure is suspected.
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The long-term solution to allergies
Instead of masking symptoms, immunotherapy retrains your immune system.
Standard allergen immunotherapy (SLIT or SCIT) is not an established treatment for biocide contact allergy. Isothiazolinones and formaldehyde releasers are small reactive chemical haptens rather than complete protein allergens; there are no standardized immunotherapy formulations for these chemicals, and no published clinical trials of desensitization for MI or formaldehyde releaser contact allergy. The treatment model remains avoidance-based. However, for patients who have co-existing IgE-mediated allergic conditions — such as atopic dermatitis driven by dust mite or environmental IgE sensitization — sublingual immunotherapy targeting those underlying conditions may improve overall skin health and barrier integrity, reducing the threshold at which biocide exposures cause clinically significant reactions. Sublingual immunotherapy, offered by providers like Curex, delivers custom-formulated allergen drops under the tongue and can be taken at home — eliminating weekly clinic visits required for allergy shots. Plans typically start at $39/month and are covered by most insurance. For patients with both biocide contact allergy and underlying atopic IgE-mediated disease, treating the IgE component with SLIT can be a meaningful part of comprehensive allergy management — even though SLIT does not address the contact sensitization itself.
Identify all biocide allergens with patch testing
Complete patch testing including MI alone, MCI/MI combined, BIT, and formaldehyde/releasers establishes the full sensitization profile.
Systematically replace all allergen-containing products
Working through cosmetics, cleaning products, and household items to identify and replace MI/BIT/formaldehyde releaser-containing products.
Evaluate for underlying IgE-mediated conditions
If atopic dermatitis or IgE-mediated allergies co-exist, consider SLIT to reduce the atopic background that amplifies contact allergy severity.
Maintain barrier and monitor for new product exposures
Ongoing label reading, consistent emollient use, and awareness that product reformulations may reintroduce allergens over time.
“Contact allergy avoidance with verified allergen-free products resolves active eczema in the majority of cases within 4–12 weeks”
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Daily Life With MI and Formaldehyde Releaser Contact Allergy
Living with biocide contact allergy primarily means becoming a diligent ingredient label reader — a habit that becomes second nature for most patients over time. The ACDS Contact Allergy Management Program (CAMP) database is an invaluable resource: after patch testing identifies specific allergens, CAMP can generate a customized list of allergen-free products across product categories, reducing the burden of individual label checking. Product reformulation is an ongoing challenge: manufacturers change formulations without notice, so a product that was safe at one time may later contain the allergen. Periodic re-checking of trusted products, especially when packaging changes, is worthwhile. For occupational MI exposure in painting, discussing MI-free paint specifications with employers or clients, or switching to low-MI/MI-free products when personal purchasing control is available, is the key workplace adaptation.
The CAMP database is your best resource
After your dermatologist performs patch testing, the ACDS Contact Allergy Management Program (CAMP) generates a personalized list of products free of your confirmed allergens. This is significantly more efficient than checking individual product labels and is the standard of care recommendation after patch testing.
Know the EU regulatory context
EU-formulated products (check packaging country of manufacture) are more likely to be MI-free for leave-on products because of the EU 2017 ban. US-formulated products may still contain MI at up to 100 ppm in leave-on products — the regulatory environment matters for product safety.
Manage relationships with personal care services
Informing hair salons, massage therapists, facial estheticians, and other personal care providers about your MI allergy before services allows them to check product labels in advance — preventing exposure during services that use high-volume products not under your direct control.
Seasonal Patterns
January - December
high intensity
March - May
high intensity
June - August
high intensity
Prevention Tips
Read ingredient labels for MI under all names
MI appears as 'methylisothiazolinone,' 'MIT,' and 'neolone 950.' MCI appears as 'methylchloroisothiazolinone.' BIT appears as 'benzisothiazolinone.' Know all synonyms.
Recognize formaldehyde releasers by name
Quaternium-15 ('Dowicil 200'), DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, and bronopol all release formaldehyde — patients sensitized to any one should avoid all.
Do not assume 'natural' means allergen-free
Many 'natural' and 'organic' products contain MI or BIT as preservatives; the 'natural' label has no regulatory definition in the US and does not guarantee biocide-free formulation.
Be vigilant about water-based paints
DIY painters should be aware that water-based interior paints commonly contain MI at high concentrations. Ventilate painting areas well and wash skin after paint contact. Low-MI or MI-free paint formulations are available.
Use ACDS and CAMP resources
The American Contact Dermatitis Society (ACDS) Contact Allergy Management Program (CAMP) provides allergen-free product databases — use these after patch testing to find safe product alternatives systematically.
Do not replace parabens with unproven alternatives
Parabens have a strong safety track record at ~1% sensitization. Replacing them based on marketing fears may expose you to worse alternatives — consult the ACDS for evidence-based guidance.
Prognosis for Biocide Contact Allergy
The contact sensitization to MI and formaldehyde releasers is lifelong — once sensitized, the immune memory persists. However, the prognosis for quality of life is good with comprehensive allergen avoidance. The vast majority of patients with diagnosed MI contact allergy experience complete resolution of active dermatitis within 4–12 weeks of successfully eliminating all allergen-containing products. Maintaining remission requires permanent vigilance about product ingredients. Inadvertent re-exposures — from a new product containing MI, a reformulated trusted product, or an occupation-related exposure — produce flares that are managed the same way: stop exposure, treat the acute dermatitis, and resume avoidance. The broader epidemiological prognosis is concerning: BIT rates (10.4% NACDG 2019-20) are approaching early MI epidemic levels. Without proactive regulatory intervention similar to the EU's MI restrictions, a BIT epidemic similar to MI's appears likely in the US over the next decade.
Key takeaways
MI sensitization peaked at 15.0% (NACDG 2017-18) — driven by consumer 'paraben-free' demand replacing parabens with a far more potent sensitizer
BIT is emerging as a replacement for MI with sensitization rates of 10.4% (NACDG 2019-20) — potentially the next epidemic allergen
MCI/MI patch testing misses ~40% of MI-only allergies — separate MI testing at 0.2% aqueous is essential for complete diagnosis
Comprehensive allergen avoidance using the ACDS CAMP database resolves active dermatitis in the majority of cases within weeks
Parabens — with ~1% sensitization — have proven far safer than their replacements; the 'paraben panic' caused the MI epidemic
The methylisothiazolinone epidemic is the clearest example of how consumer marketing caused a public health crisis — parabens were safe at 1 percent sensitization, but 'paraben-free' labeling drove a switch to MI, which peaked at 15 percent. I now test every eczema patient with separate MI at 0.2 percent, because standard MCI/MI misses 40 percent of MI-only cases.
Frequently Asked Questions
Methylisothiazolinone (MI) is a biocide preservative used in cosmetics, personal care products, household cleaners, and industrial products to prevent microbial contamination. It became a major problem when consumer demand for 'paraben-free' products drove its widespread adoption in the mid-2000s, based on incomplete safety data. MI proved to be a potent contact sensitizer: rates peaked at 15.0% in NACDG patch test populations by 2017-18 — among the highest ever recorded for a common contact allergen. The EU banned MI from leave-on cosmetics in 2017; the US has no equivalent restrictions, and rates remain high.
The hallmark of cosmetic preservative contact allergy is eczema that appears at product use sites — face from moisturizers, scalp from shampoos, hands from soaps — typically 24–72 hours after product application (not immediately, which would suggest irritation). If reactions consistently follow a specific product or product category, patch testing by a dermatologist can identify the exact causative ingredient. Standard testing covers MI, MCI/MI combined, formaldehyde, and formaldehyde releasers. Confirming the specific allergen allows targeted product replacement rather than broad avoidance of all cosmetics.
MCI/MI (Kathon CG) is a combination of methylchloroisothiazolinone and methylisothiazolinone at 3:1 ratio, tested at 100 ppm aqueous in standard patch test panels. However, this combined test misses approximately 40% of patients sensitized to MI alone — because the MCI component can mask or dilute the MI response. Separate MI testing at 0.2% aqueous is essential to capture MI-only allergies. Always confirm with your dermatologist that both MCI/MI and MI alone are included in your patch test panel if isothiazolinone allergy is suspected.
Caution is warranted with 'formaldehyde-free' claims. Many products labeled 'formaldehyde-free' contain formaldehyde releasers — chemicals that slowly release formaldehyde as they break down in the product matrix. These include quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, and bronopol. Patients sensitized to formaldehyde will react to these releasers even when 'formaldehyde' itself does not appear on the ingredient list. A positive formaldehyde patch test requires avoidance of formaldehyde by name AND all known releasers, using the ingredient list provided by your dermatologist.
MI and MCI/MI are found in a very wide range of products: liquid hand soaps and dish soaps, shampoos and conditioners, body washes and liquid cosmetics, moisturizers and sunscreens, baby wipes and diaper wipes, household cleaning sprays, laundry detergents, water-based paints, adhesives and sealants, and industrial lubricants and cutting fluids. Reading the ingredient label is essential — look for 'methylisothiazolinone,' 'MIT,' 'methylchloroisothiazolinone,' or 'MCI' on any water-containing product. In the US there are no federal concentration limits, making label review the consumer's primary protection.
Evidence is concerning. Benzisothiazolinone (BIT) sensitization rates rose from ≤0.3% in 2014 to 5.0% in Danish patch test data and 10.4% in NACDG 2019-20 — a trajectory strikingly similar to early MI. BIT is widely used in household products, paints, and industrial cleaners as a replacement for MI following EU restrictions. Without regulatory intervention equivalent to the EU's MI action, dermatologists anticipate continued BIT rate increases. The history of biocide replacement allergens — from formaldehyde to formaldehyde releasers to MI to BIT — is a cautionary tale about repeated replacement with inadequately tested alternatives.
Yes. Water-based interior paints commonly contain MI at relatively high concentrations as an in-can preservative. During application, aerosolized MI can deposit on facial and skin surfaces; brush and roller application involves direct hand exposure. Professional painters and DIY renovators with heavy paint exposure represent a meaningful occupational and hobby exposure route for MI sensitization. Airborne MI from paint can produce 'airborne contact dermatitis' — facial and eyelid eczema without direct skin-paint contact. Low-MI or MI-free paint formulations are available for sensitized individuals.
Parabens (methylparaben, propylparaben, etc.) have sensitization rates of approximately 1% in patch-tested populations — compared to MI's peak of 15.0%. The ACDS named parabens the 2019 (Non) Allergen of the Year specifically to counter 'parabenoia' — the consumer fear that drove paraben replacement with significantly worse sensitizers. Large EU and US safety reviews (including CIR 2020) confirm parabens are safe at current cosmetic use levels. The irony of the MI epidemic is that the preservative it replaced (parabens) was far safer, and the 'natural' and 'paraben-free' marketing claims that drove the switch created a genuine public health problem.
The ACDS (American Contact Dermatitis Society) Contact Allergy Management Program (CAMP) is the gold standard resource — available through dermatologists post-patch testing. Consumer databases like EWG Skin Deep can help identify products, though accuracy varies. For everyday products, look for 'free and clear,' 'preservative-free,' or 'sensitive skin' labels — then verify by checking the ingredient list. Products from countries with stricter preservative regulation (EU-manufactured products) tend to have lower MI rates for leave-on formulations, since the EU banned MI from leave-on cosmetics in 2017.
Medical References
- [1]Aerts O, Meert H, Goossens A, et al. Methylisothiazolinone in rinse-off products causes contact allergy and allergic contact dermatitis: a systematic review and meta-analysis. Contact Dermatitis. 2017;76(5):296–307.
- [2]Warshaw EM, DeKoven J, Atwater AR, et al. North American Contact Dermatitis Group patch test results, 2017-2018. Dermatitis. 2021;32(2):111–123.
- [3]Lundov MD, Krongaard T, Menne T, Johansen JD. Methylisothiazolinone contact allergy: a review. Br J Dermatol. 2011;165(6):1178–1182.
- [4]Castanedo-Tardana MP, Zug KA. Methylisothiazolinone. Dermatitis. 2013;24(1):2–6.
- [5]Warshaw EM, DeKoven J, Atwater AR, et al. North American Contact Dermatitis Group patch test results, 2019-2020. Dermatitis. 2023;34(2):90–104.
- [6]European Chemicals Agency (ECHA). Annex XV Restriction Report on Methylisothiazolinone in leave-on cosmetic products. ECHA, 2016.
- [7]De Groot AC. Myroxylon pereirae resin (balsam of Peru) and other contact allergens in fragrances. Dermatitis. 2018;29(1):3–13.
This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. Content reviewed by board-certified allergists at Curex.
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