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Contact Dermatitis — SCE Dermatology MCQ

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ModerateInflammatory DermatosesContact DermatitisSCE Dermatology

A 58-year-old man presents with dermatitis that localises to the dorsal feet bilaterally and has been present for 6 months. He wears leather shoes daily. Patch testing is positive to potassium dichromate and mercaptobenzothiazole. What advice should be given?

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Correct answer: C — Avoid chromate-tanned leather shoes and rubber components in footwear

Potassium dichromate is a sensitiser present in chromate-tanned leather, and mercaptobenzothiazole is found in rubber components of shoes (soles, adhesives). A positive patch test to both indicates shoe contact dermatitis requiring avoidance of both chromate-tanned leather (switch to vegetable-tanned or synthetic leather) and rubber shoe components (switch to shoes with non-rubber soles). Cotton or vinyl socks can provide a barrier. Rubber sandals would worsen mercaptobenzothiazole allergy. Complete allergen avoidance information sheets should be provided from the patch test clinic.

Reference: BAD 2017 Contact Dermatitis Guidelines