Eugenol Allergy — ORE Part 1 MCQ

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HardHuman Disease & Dental ManagementEugenol AllergyORE Part 1

A patient develops widespread urticaria and mild lip swelling within minutes of placement of a temporary restoration. There is no wheeze, stridor, hypotension or gastrointestinal symptom. The temporary restoration was placed using a zinc oxide–eugenol material. Which component is the most likely cause of the reaction?

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Correct answer: D — Eugenol in the temporary cement

The correct answer is **A. Eugenol in the temporary cement**. Zinc oxide–eugenol materials are used in UK dental practice, and eugenol is a recognised irritant and sensitiser. The immediate onset of urticaria and lip swelling after direct exposure makes eugenol the most likely implicated component. The absence of airway, circulatory or gastrointestinal features means the presentation is not, on the stated facts, anaphylaxis, although it requires prompt assessment and monitoring for progression. Fluoride release and silicate filler are not credible explanations for this acute pattern. A stainless-steel matrix band could exceptionally be relevant in metal contact allergy, but it is less consistent with the temporal association to a eugenol-containing temporary cement and with acute generalised urticaria. Aluminium from the retainer is similarly implausible. The prior peanut allergy should not be used to infer eugenol cross-reactivity; eugenol hypersensitivity is a separate sensitisation phenomenon.

Reference: Clove Oil BP. Summary of Product Characteristics, sections 4.3 and 4.8, electronic Medicines Compendium (UK), current. https://www.medicines.org.uk/emc/product/4817/smpc