by Terrence Aym

Created on: November 30, 2010

Pop quiz: What can a hair shampoo do for you besides cleaning, conditioning, and making your hair smell great?

Answer: It might cause eczema on your scalp and hands too.

A study released from a research team in Sweden has found a strong link between some hair products available on the marketplace and the incidence of eczema. For several decades, eczema—a reaction in the skin that creates a condition of reddish scaliness—was thought to be primarily caused by allergies in the diet or simply a malfunctioning immune system. Histamines were the primary culprit.

Although it was known for some time that those already suffering from eczema could worsen the symptoms by exposing their skin to water or bringing it in contact with certain chemicals, no real association was made between the malady and certain chemical agents that might actually cause eczema.

The Swedish study conducted by researchers at the Sahlgrenska Academy* at the University of Gothenburg, specifically looked for such a connection—if one existed—and found evidence that it does exist.

The study developed a special skin test to measure subjects' reaction to "linalool" (an oxidized fragrance used in many types of consumer hair and cosmetic products). [1] Upon analysis of the results, the researchers found that about 5 to 7 percent of the tested subjects had an adverse reaction to linalool.

Linalool is an ingredient in thousands of products available at beauty supply stores, drug stores and supermarkets.

What makes this research finding alarming, the team points out, is that as much as 80 percent of the products on the market (including hair shampoo and rinses, moisturizers, cleansers, soaps, make-up, perfume, cologne, aftershave and beauty cream) contain linalool. Cumulative exposure to the substance over a period of years can create a sensitivity to it. Eventually some individuals will develop eczema from their long term exposure to linalool. [2]

Linalool, a plant extract derived from a variety of plants including lavender, becomes an irritant when it oxidizes. [3] [4]

Experts recommend you read product labels carefully and try to avoid using too many that contain linalool. If that's not feasible, limit the oxidation that causes the eruption of eczema by never leaving the product's cap off and keeping the product in a darkened, cool area.

Natural oils and plant extracts oxidize when exposed to air, light and heat.

* The Sahlgrenska Academy is the faculty of health sciences at the University of Gothenburg. Education and research are conducted within the fields of pharmacy, medicine, odontology and health care sciences.

Sources

[1] "Oxidized linalool - a significant contact sensitizer." Bråred Christensson J, Matura M, Gruvberger B, Bruze M, Karlberg A-T. Manuscript.

[2] Risk assessment of linalool - EPA [PDF]

[3] "Air oxidation increases skin irritation from fragrance terpenes" Bråred Christensson J, Forsström P, Wennberg A-M, Karlberg A-T, Matura M. Contact Dermatitis: 2009: 60: 32-40.

[4] "Hydroperoxides form specific antigens in contact allergy." Bråred Christensson J, Matura M, Bäcktorp C, Börje A, Nilsson JLG, Karlberg A-T. Contact Dermatitis: 2006; 55(4): 230-7.

Link

"Widely Used Fragrance Ingredients In Shampoos And Conditioners Are Frequent Causes Of Eczema"

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