Even natural perfumes may cause allergies

Roughly one in five adults in northern Europe is believed to suffer from contact allergy to one or more chemicals. The most common is nickel allergy, but many people also suffer from contact allergy to perfumes – even perfume substances that at first glance appear to be harmless can cause allergic reactions. New eczema-provoking allergens are formed by reaction with acid in the ambient air (known as autoxidation) or with skin enzymes.

Natural aromas not safer
Modern society commonly regards anything that comes from nature as being healthier and less dangerous. Where it concerns natural aromas, known as essential oils, many manufacturers believe that natural antioxidants in these oils offer protection against autoxidation thus making them safer and longer lasting than artificial perfumes. Research at the University of Gothenburg shows this is not the case.
Reaction with the skin
Lina Hagvall, a researcher at the University of Gothenburg's Department of Chemistry, has examined natural lavender oil in her thesis. Her results show that essential oils do not prevent the formation of allergenic substances through reactions with acid; something which had not previously been possible to confirm. Hagvall's thesis also examines geraniol, a common constituent of perfumes such as rose oil.

The study shows geraniol by itself to be only slightly allergenic. However through autoxidation and reaction with skin enzymes, the substance is activated and becomes the closely related allergen geranial. This is the first time these activation pathways have been demonstrated for the substance.

More perfumes can be allergene
It is important to investigate how perfumes react with air or on skin. Lina Hagvall's thesis concludes that such risks must be factored into health risk assessments of chemicals relating to contact allergy. The thesis also demonstrates that more perfumes than previously believed can be activated into allergens, and that more studies should be done to increase knowledge within the field and thus reduce the number of eczema cases.

Hagvall's thesis, Formation of Skin Sensitizers from Fragrance Terpenes via Oxidative Activation Routes. Chemical analysis, Structure Elucidation and Experimental Sensitization Studies was defended on the January 30th. The supervisor was Ann-Therese Karlberg, professor of dermatochemistry and head of the research platform Göteborg Science Centre for Molecular Skin Research at the University of Gothenburg.

Contact details
Lina Hagvall, Department of Chemistry, University of Gothenburg, Sweden
+46 (0)31 772 38 49
lina.hagvall@chem.gu.se