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Allergy Testing & Patch Testing Flashcards

7 cards from real CDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Allergy Testing & Patch Testing flashcards as text

  1. Which metal is the most common contact allergen identified by patch testing worldwide?

    Answer: Nickel

    Nickel is the most prevalent contact allergen worldwide, commonly found in jewelry, belt buckles, watches, and metal fasteners.

  2. Para-phenylenediamine (PPD) is a common patch test allergen primarily found in:

    Answer: Permanent hair dyes

    PPD is a key ingredient in permanent dark hair dyes and is one of the most common causes of contact dermatitis from hair coloring products.

  3. Balsam of Peru is included in patch test panels primarily because it serves as a marker for sensitivity to:

    Answer: Fragrances, spices, and aromatic compounds

    Balsam of Peru is a natural resin that cross-reacts with many fragrances, spices, flavorings, and topical preparations containing similar aromatic compounds.

  4. A patient has a positive patch test to thiuram mix. This result indicates sensitivity to:

    Answer: Chemical accelerators used in rubber vulcanization

    Thiuram compounds are chemical accelerators added during the rubber vulcanization process, so thiuram mix sensitivity indicates rubber accelerator allergy rather than natural latex protein allergy.

  5. Which preservative commonly found in rinse-off and leave-on cosmetics has become a leading cause of contact allergy?

    Answer: Methylisothiazolinone (MI)

    Methylisothiazolinone (MI) is a preservative widely used in personal care products that became epidemic as a contact allergen after its expanded use in leave-on cosmetics.

  6. A healthcare worker with hand dermatitis tests positive to carba mix on patch testing. The most likely source of occupational exposure is:

    Answer: Rubber examination gloves

    Carba mix contains carbamate accelerators used in rubber glove manufacturing, making examination gloves the primary occupational exposure source for healthcare workers.

  7. Topical corticosteroids at the patch test application site should be:

    Answer: Discontinued for at least 1–2 weeks before testing on that skin area

    Topical corticosteroids suppress the local immune response and can cause false-negative patch test results, so they must be stopped at least 1–2 weeks before testing in that area.