Fragrances as allergens

Abstract

Contact allergies due to fragrances are common. If one adds up the reaction incidences of the indicators of fragrance allergy (fragrance mix [FM] I + II, balsam of Peru and turpentine), these reach 17% in a hospital collective (Information Network of Departments of Dermatology [IVDK] data 2016) and are thus higher than those for nickel allergy (approximately 16%). In the case of positive reactions to FM I, >50% do not react to one of the components. This type of reaction should be interpreted as allergic with caution, unless other data (e. g., positive history, application test) support this interpretation. FM-I-positive individuals often react to oak moss (27.2%) and isoeugenol (18.2%). These are followed by hydroxycitronellal (10.9%), cinnamal (10.6%), cinnamyl alcohol (8.4%), eugenol (7.3%), geraniol (5.5%), and amyl cinnamal (1.5%). The frequency of sensitization (SF) to the individual fragrances depends on their allergenic potency (measured using the local lymph node assay, LLNA) and the frequency of use (extent of exposure). The relationship between SF and exposure is described by the sensitization exposure quotient (SEQ). The SEQ is a measure of the risk of sensitization. In general, it correlates with the SF on the one hand and with the allergenic potency (hazard) on the other. Exceptions to this rule indicate a newly recognized problem: (1) Although methyl 2-octynoate plays no role in SH statistics, it came third after tree moss and oak moss with its SEQ (=risk); (2) despite its low potency, hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral®) had a relatively high risk. In this particular case, potency (the inherent hazard) was not the determinant of risk, but rather the overly high doses used. Allergy monitoring by clinical epidemiology needs to be more heavily supplemented by data on exposure.