Comments on Various Baseline Series for Patch Testing

National baseline series, often based on continental baseline series, usually contain contact allergens to which patients from a particular region are exposed, and that frequently elicit positive and/or relevant patch test reactions. Differences between national baseline series can be explained, among others, by differences in exposure, prescribing habits of physicians, and the (non-)availability of contact allergens. Particularities of baseline series from the following countries are discussed in this chapter: Belgium, Denmark, France, Germany, Hungary, Italy, the Netherlands, Poland, Portugal, Slovenia, Spain, Sweden, UK, USA, Australia, Brazil, and Mexico. Furthermore, differences in patch testing may also refer to what vehicle and/or concentration are used to patch-test a given contact allergen. Examples, discussed in this chapter, include metals, hair dyes, rubber components, pharmaceuticals, (meth)acrylates, preservatives, vehicle components, fragrances, and textile dyes. All these considerations should be taken into account when comparing patch test data from different countries.