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MI Contact Allergy — SCE Dermatology MCQ

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EasyInflammatory DermatosesMI Contact AllergySCE Dermatology

A 30-year-old woman with chronic hand eczema is patch tested and found to be allergic to methylisothiazolinone (MI). This allergen was declared Contact Allergen of the Year in 2013. What products commonly contain MI?

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Correct answer: B — Cosmetics, wet wipes, household cleaning products, paint, and personal care products (shampoo, body wash, moisturisers) — MI is one of the most prevalent contact allergens

Methylisothiazolinone (MI) is a preservative that became one of the most prevalent contact allergens worldwide, leading to an epidemic of MI contact allergy. It is found in: cosmetics and personal care products (shampoos, moisturisers, sunscreens, wet wipes), household products (cleaning agents, dishwashing liquid, laundry detergent), industrial products (paints, adhesives, metalworking fluids), and some medical devices. The EU banned MI from leave-on cosmetics in 2016 and restricted concentrations in rinse-off products, leading to declining sensitisation rates. Patients must receive comprehensive avoidance advice covering all potential MI-containing product categories.

Reference: BAD 2017 Contact Dermatitis; ESCD; ACD Contact Allergen of Year