[Eugenol in root canal cement:possible cause for urticarial reactions].

A case is reported of a patient with chronic urticaria. The correlation between the symptoms and dental treatment gave rise to the supposition that a root canal cement was causing the trouble. This hypothesis has been tested with epicutaneous patch tests and intradermal tests in cooperation with the Utrecht University Hospital (the Netherlands), Institute of Dermatology, Clinical Allergy Section. A causal relationship with eugenol, a cement constituent, could only be established through provocative oral ingestion. Nevertheless, caution is needed when dealing with chronic urticaria in view of the risk of anaphylactic reaction. Consequently, the article highlights the allergenic aspects of eugenol, as a substance associated with balsam of Peru. Attention is focused on the fact that eugenol, used in dental materials, is able to elicit and maintain urticaria protractedly.