Allergen of the Year: Fragrance

Frances J. Storrs


Dermatitis. 2007;18(1):3-7. 

In This Article

Relevance of Positive Reactions to Fragrance Mix Patch Tests

The NACDG designates "present" relevance for an allergen as "definite" when the product or object use-test reaction or patch-test reaction is also positive, as "probable" when the allergen is found to be present in the patient's contactants, and as "possible" when the allergen is likely to be in the patient's environment.[7] For all categories, the distribution of the dermatitis must fit as well. Although present relevance (the combination of definite, probable, and possible relevance) in the 2001-2002 NACDG data is 83.5% for fragrance mix, definite relevance is only 1.8%, probable relevance is 17.2%, and possible relevance is 64.5%.[7] In fact, in North America we have no idea what is in most fragrances, and thus even designations of probable relevance are suspect. Actual perfumes or fragrances added to products are seldom used in patch testing by the NACDG.

Even the most critical reviews of NACDG fragrance data lump all relevance categories together and cite a present relevance of 64 to 87%, depending on the data set reviewed.[1,6]

Before the presentation of the NACDG's 1998-2000 data in 2003, the definite, probable, and possible relevance categories were lumped together as "present" relevance.[10] The categories are now separate, and the most recent data report contains this comment: "The relevance of fragrance allergy is difficult to determine, and because this is done inconsistently, the relevance values are highly controversial."[7]

In Europe, analytical studies showed that patients with positive results on fragrance mix patch tests were using products that almost always contained one to six of the fragrance mix constituents, which explained their then present or past episodes of dermatitis.[11] The patients also had positive patch-test or use-test reactions to the products; thus, all criteria for definite present relevance were met.

Such studies have not been done in North America. Fragrance ingredients are similar but different in North America and in Europe.[6] Until we analyze the fragrance ingredients of products in North America and test patients with them, as has been done in Europe with European products, we must question the actual prevalence and relevance of true fragrance allergy here.


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