Strategy to decrease the risk of adverse effects of fragrance ingredients in cosmetic products.

In spite of extensive self-regulation of the fragrance industry, fragrance ingredients are still major causes of allergic contact dermatitis. There are indications that the problem is increasing in some countries, and that many nonregulated compounds are involved in the development of allergies. The use of essential oils in fragrance compounds might add both allergenic and carcinogenic compounds to a product and the exact composition of such ingredients is difficult to control. Herein, we propose a simple strategy to decrease the risk of adverse effects of fragrance ingredients in cosmetic products. This strategy consists of four major steps: (1) limit the concentration of fragrance compound in the products, (2) follow legislation and guidelines, (3) limit the concentration of a number of well-known sensitizing fragrance chemicals, and (4) limit the concentration of essential oils and materials with unknown composition. The strategy is discussed as an alternative to animal testing and in relation to other more resource-demanding approaches to the same problem.

Barrier recovery and influence of irritant stimuli in skin treated with a moisturizing cream.

Moisturizers are used daily by many people to alleviate symptoms of clinically and subjectively dry skin. Recent studies suggest that certain ingredients in creams may accelerate the recovery of a disrupted barrier and decrease the skin susceptibility to irritant stimuli. In the present single-blind study, a moisturizing cream was tested for its influence both on barrier recovery in surfactant-damaged skin and on the susceptibility of normal skin to exposure to the irritant sodium lauryl sulphate (SLS). Parameters measured were transepidermal water loss (TEWL) and skin corneometer values, indicating degree of hydration. Treatment of surfactant-damaged skin with the test cream for 14 days promoted barrier recovery, as observed as a decrease in TEWL. Skin corneometer values also normalized more rapidly during the treatment. In normal skin, use of the test cream significantly reduced TEWL after 14 days of treatment, and irritant reactions to SLS were significantly decreased. Skin corneometer values increased after only 1 application and remained elevated after 14 days. In conclusion, the accelerated rate of recovery of surfactant-damaged skin and the lower degree of SLS-induced irritation in normal skin treated with the test cream may be of clinical relevance in attempts to reduce contact dermatitis due to irritant stimuli.

Effect of topically applied lipids on surfactant-irritated skin.

Moisturizers are used daily by many people to alleviate symptoms of dry skin. All of them contain lipids. It has been suggested that topically applied lipids may interfere with the structure and function of the permeability barrier. The influence of a single application of nine different lipids on normal skin and skin irritated by sodium lauryl sulphate (SLS) was studied in 21 healthy subjects. Parameters assessed were visible signs of irritation, and objectively measured cutaneous blood flow and transepidermal water loss (TEWL). The substances tested were hydrocortisone, petrolatum, fish oil, borage oil, sunflower seed oil, canola oil, shea butter, and fractions of unsaponifiable lipids from canola oil and shea butter. Water was included as a control. On normal skin, no significant differences in the effects of the test substances were found, whereas significant differences were observed when they were applied to SLS-irritated skin. The visible signs of SLS-induced irritation were significantly less pronounced after treatment with the sterol-enriched fraction from canola oil than after treatment with water. This fraction, and hydrocortisone, reduced cutaneous blood flow. Furthermore, application of hydrocortisone, canola oil, and its sterol-enriched fraction, resulted in significantly lower TEWL than with water. The other lipids had no effect on the degree of irritation. In conclusion, lipids commonly used in moisturizers may reduce skin reactions to irritants. Previous studies have shown that, in barrier perturbed skin, the synthesis of sterols is increased. The observed effects of canola oil and its fraction of unsaponifiable lipids on SLS-induced irritation suggest the possibility that they assisted the skin in supplying the damaged barrier with adequate lipids.