Skin patch screening test for allergy to fragrances - second only to nickel as the most common cause of contact dermatitis in the Western world - may not detect some cases of allergy to a widely used fragrance chemical, Swedish scientists are reporting. In a study published in ACS' Chemical Research in Toxicology, Ann-Therese Karlberg and colleagues focus on geraniol, a chemical in Fragrance Mix I (used for allergy skin patch testing). Because of its fresh, floral scent, geraniol is widely used in household products, underarm deodorants and cosmetics, the report states. Geraniol has been regarded as a weak allergen, responsible for only about 5 percent of positive patch test responses to the fragrance allergens used for screening of fragrance allergy in dermatitis patients. The new research, however, shows that geraniol oxidizes during exposure to air, changing into a more potent allergen. "Cases of allergy to the oxidation products of geraniol will not be diagnosed unless patients are tested with the air-exposed material," the report states. "Thus, our observations once more emphasize the need for testing with the right material for screening contact allergy." ARTICLE: "Fragrance Compound Geraniol Forms Contact Allergens on Air Exposure. Identification and Quantification of Oxidation Products and Effect on Skin Sensitization" CONTACT: Ann-Therese Karlberg, Ph.D. Göteborg University Göteborg, Sweden ### American Chemical Society News Service The American Chemical Society - the world's largest scientific society - is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio. Contact: Michael Woods