The analysis and technical support for this study were done by the Spanish Academy of Dermatology (Research Unit). C. Galv an Casas and A. Catal a contributed equally as first authors.

Background. The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in consecutive patients in the years 2007 and 2008, and to discuss possible differences. Methods. Data from the 39 departments in 11 European countries comprising the European Surveillance System on Contact Allergy network (http://www.essca-dc.org) in this period have been pooled and analysed according to common standards. Results. Patch test results with the European baseline series, and country‐specific or department‐specific additions to it, obtained in 25 181 patients, showed marked international variation. Metals and fragrances are still the most frequent allergens across Europe. Some allergens tested nationally may be useful future additions to the European baseline series, for example methylisothiazolinone, whereas a few long‐term components of the European baseline series, namely primin and clioquinol, no longer warrant routine testing. Conclusions. The present analysis points to ‘excess’ prevalences of specific contact sensitization in some countries, although interpretation must be cautious if only few, and possibly specialized, centres are representing one country. A comparison as presented may help to target in‐depth research into possible causes of ‘excess’ exposure, and/or consideration of methodological issues, including modifications to the baseline series.

The inclusion of methylisothiazolinone as a preservative in cosmetics might not represent the solution to the problem of allergic contact dermatitis from isothiazolinones, since it leads to primary sensitization.

Allergic contact dermatitis caused by sulfites is frequent and often relevant. One should be aware of possible relevant sources of exposure, particularly in occupational settings such as hairdressing and the food industry, and in pharmaceutical and cosmetic products. Patch testing with sodium metabisulfite, which seems to be the best indicator for sulfite contact allergy, is also useful in cases of immediate reactions to sulfite-containing products.

No abstract