Swedish scientists have issued warnings on common household personal care products that may be responsible for eczema - among them being several shampoos, skin conditioners and soaps. These supposedly contain an ingredient that can cause eczema.
A thesis presented at the Sahlgrenska Academy, University of Gothenburg, Sweden found that over 5 percent of those who underwent patch testing were allergic to the air oxidized form of the fragrance ingredient linalool.
Eczema can cause a lot of different skin conditions, including rashes, swelling, itching and cracking.
"I would suspect that about 2 percent of the complete population of Sweden are allergic to air oxidized linalool. That may not sound very much, but it is serious since linalool is so widely used as a fragrance ingredient. Linalool is found in 60-80 percent of the perfumed hygiene products, washing up liquids and household cleaning agents that can be bought in the nearest supermarket, and it can be difficult for people who are allergic to avoid these products", says dermatologist Johanna Brared Christensson, author of the thesis.
Nickel is by far the most common substance that causes eczema, but the thesis shows that oxidized linalool occupies third place in the list, after nickel and cobalt.
In the study, oxidized linalool was added at patch testing for more than 3,000 patients who wanted to find out what was causing their eczema. Between 5 percent and 7 percent proved to be allergic to the oxidized form of the fragrance ingredient.
"Linalool is present in many products around us, and this is probably the reason that contact allergy to this material is so common. Some people can shower with shower cream that contains linalool but never develop contact allergy, but we know that the risk increases as the exposure to t! he substance increases", says Johanna.
Linalool is a fragrance ingredient found naturally in lavender, mint, and other plants. Linalool breaks down when it comes into contact with oxygen, it becomes oxidized and can cause allergy. Manufacturers do include other substances in the products to delay this oxidation process, but allergenic substances can stiill be formed from linalool when it is stored.
"One way of trying to minimize exposure to oxidized linalool is to avoid buying large packs of soap and shower cream, and always to replace the top after using a bottle", says Johanna.