By Margarita Nahapetyan
Linalool, an ingredient that is most commonly used in shampoos, conditioners and soap to boost scent, can cause allergy and eczema in many individuals, caution experts from the University of Gothenburg in Sweden.
Linalool is a fragrance ingredient that is extracted from lavender, mint, and some other plants. It breaks down when it comes in contact with oxygen and, therefore can cause allergic reactions and even eczema. Manufacturers do include other substances in the cosmetic products in order to prevent or to delay the oxidation process, but allergic substances can still be formed from linalool when it is being stored for a long time. And while nickel and cobalt are considered to be the most common substances to be responsible for eczema, a new study claims that oxidized linalool is the substance number three on this list.
To come up with this conclusion, the experts added oxidized linalool at patch testing for more than 3,000 patients who were eager to find out what was the real cause of their eczema. Eczema is an acute or chronic inflammatory condition of the skin that is characterized by rashes, swelling, itching and cracking.
Dermatologist Johanna Christensson, the main author of the thesis which has been presented at the Sahlgrenska Academy, University of Gothenburg, found that between 5 per cent and 7 per cent of people who underwent patch testing for allergic reactions, proved to be allergic to the oxidized form of the fragrance ingredient linalool. This could only mean that more than 15 million people in the United States may be suffering from eczema as a result of common ingredients in shampoos, conditioners, and household cleaning products that they use on a daily basis.
Linalool is found in 60 to 80 per cent of the perfumed hygiene products, washing up liquids and household cleaning agents that can be purchased in the nearest store. According to Christensson, linalool is present in too many products that are of a constant use, and this must be the main reason why the contact allergy to this substance is so common. However, some individuals can use cosmetic products that contain linalool but never develop contact allergy, but there are people that are affected to extremely high extent. "We know that the risk increases as the exposure to the material increases", the dermatologist said.
Legislation of European Union states that manufacturers must post on the labels of hygiene and cosmetic products whether they contain linalool. Previous research has indicated that oxidized linalool may cause contact allergy in about 1 per cent of patients with eczema. Scientists suggest that people should not purchase large packs of soap and showering cream or gel, and also advise to replace the cap after using a bottle. In their opinion, these simple steps could help minimize exposure to oxidized linalool and subsequent eczema.