Skin Patch Tests May Miss Patients Allergic To Common Fragrance

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.” (Source: Chemical Research in Toxicology : Goteborg University : June 2007.)