Impact of Fragrance on the Skin

Absorption

How much of a material is absorbed through the skin depends on numerous factors. In general, large molecules are not readily absorbed into the skin and materials must have some fat solubility to be absorbed. Materials in mixtures may absorb differently than single materials. The concentration of the material, length of exposure, condition and location of the skin also play vital roles in absorption. Moisture and heat also increase absorption. Logically the larger the area of exposure, the more material will be absorbed. Areas that are covered or occluded after application may absorb more than included areas.

Perfumes and colognes are often applied to the skin. These products represent only a fraction of the exposures to fragrance. Soaps, lotions and other toiletries have contact with large areas of the body. Clothing washed in scented products have direct contact  and cover large areas of skin. There is often prolonged skin contact with cleaners in the presence of moisture and heat. Multiple scented products come in contact with the skin on a daily basis.

Some fragrance materials are readily absorbed through the skin, while other are not. Testing shows coumarin is well absorbed through the skin at 60% while only about 3% of limonene is absorbed. However, other studies have shown that limonene disrupts the normal protective mechanisms of the skin and causes increased absorption of other materials into the skin. Mixtures will absorb differently than singular materials.

Materials that are absorbed through the skin not be immediately dispersed. The skin can act as a reservoir. The material may then be slowly released into systemic circulation. There can be continued systemic exposure long after the initial contact. Some materials enter systemic circulation quickly, while others may remain in the skin reservoir much longer. Once the materials are in the skin, they may be metabolized and broken down. Not all materials can be metabolized in the skin and remain relatively intact. Systemic exposure may be to the original substance or to the broken down compounds.

Allergies

Fragrance materials that cause allergies do so by mechanisms that are a bit different than allergies due to pollen, dander, and other protein based allergens. Allergies to protein based substances occur when the body perceives these materials as harmful and defense mechanisms are triggered. Fragrance chemicals are not usually protein based and are usually considered too small to be detected as an allergen. However, some of these materials act as a hapten (substances that bind with proteins) in the skin. The proteins in the skin are modified by the haptens and the body then treats these proteins as a foreign substance and allergic reactions are triggered.

Once such sensitization occurs, the only way to prevent allergic reactions is to avoid exposures. Unlike other allergies, those caused by haptens do not generally respond to allergy medications. Such allergies also tend to last a lifetime and often get worse with exposures. There is a direct correlation between development of skin allergies to fragrance and exposure.

An estimated 1-2% of the general population has skin allergies to fragrance. It is difficult to assess exact numbers as many people do not seek medical attention, they simply stop using the products that contain materials they are sensitive to. Fragrance is second only to nickle as a skin allergen and is the number one cause of skin allergy to cosmetics and laundry products.

The most common fragrance allergens are listed in the table below

Materials that also identified as allergens, but less frequently

Taken from
THE SCIENTIFIC COMMITTEE ON COSMETIC PRODUCTS AND NON-FOOD PRODUCTS INTENDED FOR CONSUMERS
http://europa.eu.int/comm/food/fs/sc/sccp/out98_en.pdf

Irritants

Fragrance materials are also skin irritants.