Frequency of sensitization to common allergens: comparison between Europe and the USA

Background: Previously, contact allergy to formaldehyde and quaternium-15 was found to be more prevalent in the United States than in Europe. No such data have been assessed for other contact allergens. Objective: Determine any differences in frequencies of sensitization to contact allergens in the United States and Europe. Methods: Literature study. Comparison of reported frequencies of sensitization to contact allergens routinely tested both in the United States and Europe in recent, large, multicentre studies. Because of the heterogeneity of studies and background parameters, statistical evaluation was not attempted. Results: Major differences were found only for neomycin (USA 10.0-11.8%, mean 11.4%; Europe 1.2-5.4%, mean 2.6%). Most allergens had somewhat higher prevalence in the United States, with rates versus Europe ranging from 1.3 to 1.9. Conclusions: Contact allergy to neomycin is much more prevalent in the United States. Stricter selection of patients for patch testing in United States tertiary referral centres may result in 50% more positive reactions compared to European studies.