North American beauty industry website, Cosmetics Design, reports that some essential oils can become allergenic on contact with oxygen in the air and certain skin enzymes, according to recent research from Sweden.
The research could have implications for people suffering from eczema and contact dermatitis.
The website quotes researcher Lina Hagvall, from the University of Gothenburg, Sweden, as saying that formulators should be aware that certain aromatic oils are altered by environmental factors and can cause contact allergies in sensitive individuals, even if the oil itself is not an allergen in its pure form.
Hagvall looked at lavender oil and geraniol oil (the major component of rose oil) as part of her pHD thesis and found that allergens are formed by reaction with acid in the ambient air (known as auto-oxidation) or with skin enzymes.
According to the Cosmetics Design report, Hagvall’s research found that lavender oil auto-oxidises, forming hydroperoxides, which are strong allergens. She did not investigate the behaviour of lavender oil when in contact with skin enzymes, but referenced previous studies indicating it did not form allergens under these circumstances.
Hagvall found that geraniol oil by itself is only slightly allergenic, however through auto-oxidation and reaction with skin enzymes, it is activated and becomes the closely related allergen, geranial. This is the first time these activation pathways have been demonstrated for the substance.
Hagvall was quoted on Cosmetics Design as saying, “I think that auto-oxidation should be considered by formulators and producers of essential oils… more work is needed to make sure these essential oils are used in a safer way, with regard to the development of contact allergies.”
She explained that the main risk for developing contact allergy to geraniol is through contact with air-exposed material as the concentrations of the allergens are higher. Therefore, preventing auto-oxidation is still important for geraniol.