Perfume allergy due to oak moss and other lichens

During a period of 2 1/2 years, 7 of 2000 patients routinely tested at our laboratory revealed contact allergy to oak moss in perfumes. All reacted to a mixture of different lichens and to some specific lichen compounds. The sensitivity was probably induced by cosmetics containing lichen substances. The following 3 compounds caused reactions in all patients tested: atranorin, evernic and usnic acids. 3 patients were photosensitive, but stronger reactions were elicited by prolonged contact during occlusion of the patches and complete protection against light, rather than by irradiation alone. The data suggest that the sensitizing capacity of the lichen compounds is primarily of a contact rather than of a photocontact nature.