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Atopic Eczema — SCE Dermatology MCQ

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ModerateInflammatory DermatosesAtopic EczemaSCE Dermatology

A 25-year-old woman with atopic eczema has patch testing performed due to worsening eczema despite treatment. She has positive reactions to Methylchloroisothiazolinone/Methylisothiazolinone (MCI/MI) and fragrance mix I. Her emollient contains MCI/MI as a preservative. What is the most appropriate action?

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Correct answer: A — Discontinue the emollient and switch to one without MCI/MI preservatives

When patch testing identifies relevant contact allergens in products being used by the patient, the offending product must be discontinued and replaced with an allergen-free alternative. MCI/MI is a common preservative in emollients and cosmetics that frequently causes allergic contact dermatitis, particularly in patients with impaired skin barrier (atopic eczema). Replacement products must be checked for cross-reacting preservatives. Aqueous cream should NOT be used as a leave-on emollient in eczema (contains SLS). The patient should receive a detailed allergen avoidance sheet.

Reference: BAD 2017 Contact Dermatitis Guidelines; NICE CG57