[Contact allergy to Anacardiaceae. A review and case reports of poison ivy allergy in central Europe].

In Europe, as opposed to North America, poison-ivy rash is hardly known. For this reason a detailed review of the allergenic members of the Anacardiaceae family is given, and the misleading nomenclature of "poison ivy", "poison oak", and some other species of this family are discussed. An up-to-date representation of the chemical structure of the allergenic substance group (denoted as "Urushiol") from this family is provided as well as botanical information regarding the plants themselves. Prevention of this dangerous sensitization and the therapy of this allergic reaction are discussed. The four cases presented are as follows: a young German woman who became sensitized to poison ivy or poison oak while in the USA and showed a cross reaction to other Rhus species (R. copallina, R. javanica (semialata), R. trichocarpa) as well as to Choerospondias axillaris var. japonica and to mangoes; a landscape gardener with an occupationally acquired allergy to Anacardium occidentale; and two control persons giving positive results to skin tests with Urushiol and Rhus trichocarpa respectively, to which the source of sensitization could not be clarified. Tests with three kinds of pistachio and two native-European Anacardiaceae (Rhus typhina and Cotinus coggygria) yielded negative results in each case. Prophylaxis to sensitization requires familiarity with the numerous Anacardiaceae and derivative products to which one could come in contact. These substances, summarized in a table, include mango, cashew and "sweet pepper".