52 JOURNAL OF COSMETIC SCIENCE EVALUATION AND TREATMENT OF SENSITIVE SKIN A MULTI-FACETED APPROACH D. Maes, K. Marenus, N. Muizzudin, E. Goyarts, C. Fthenakis, M. McKeever, Este• Lauder Laboratories, Melville, NY 11747 Introduction: Users of cosmetic products, often perceive their skin to be "sensitive", as they experience transient adverse reactions such as itching, burning, redness, and in some cases edema. Although some of these adverse effects do not qualify as sensitive skin reactions, we believe it is necessary to understand the etiology of these cutaneous responses, tn order to develop products which not only will be milder, but in addition will reduce the reactivity of the real 'sensitive skin". To be able to create such technology, it is necessary to understand the mechanisms of the processes leading to skin sensitivity, and to develop the methodologies which will allow the accurate measurement of the factors involved in the development of a cutaneous reaction. Skin sensitivity can be evaluated on the basis of three different parameters: Skin permeability which is controlled by the barrier function of the Stratum Corneum, skin immune reactivity which dictates what type of reaction is going to take place (irritant or allergic), and skin neuro-sensory response. We propose to first review the correlation between these three factors and the development of sensitive skin. We then will review the most recent technologies available to control these factors in order to reduce significantly the reactivity of the skin to the environment. The etiology of sensitive skin: One of the most important cause of a cutaneous reaction, is certainly the disruption of the sk{n's barrier function. Even if this factor alone cannot account for all the different aspects of sensitive skin, •t remains certainly one of the most common factor leading to the development of chronic, sensitive skin. To evaluate such correlation, we measured the Trans Epidermal Water Loss on the facial cheek area of a group of individuals with sensitive skin, after removal of successive layers of the stratum Comeurn using adhesive tape. The results clearly showed that it took significantly less strips to destroy the barrier function of the individuals with sensitive skin compared to a group with normal skin. Similarly, measurements of the skin reactivity (blood flow), clearly separate the sensitive from the non-sensitive populations, showing a clearly distinct reaction to an irritant between the two groups. Additional measurements done in-vivo after application of Methyl nicotinate on the skin, showed a significant increase in the release of two key inflammatory mediators, Arachidonic acid and Prostaglandin E2, providing some additional insight on the possible mechanism behind the previously observed increase in blood flow. Similar conclusions were obtained as far as the neuro-sensory response is concerned as the group with sensitive skin experienced a stronger stinging reaction to lactic acid than the population with normal skin.

PREPRINTS OF THE 1997 ANNUAL SCIENTIFIC MEETING 53 Treatment of sensitive skin: The diversity of the causes of a skin reaction makes the treatment of sensitive skin a fairly complex matter. It is obvious, that an efficient therapy should include various technologies which will simultaneously improve the skin's barrier function, reduce the reactivity of the skin's immune system, and finally modulate the neuro-sensory response of the skin. We intend to review in the first place, some of the technologies which strengthen the barrier function of the Stratum Corneum, resulting in a significant reduction of the skin reactivity, We will then present the different aspects of the modulation of various inflammatory mediators such as PLA2, PGE2, ILl, TNFalpha, as well as the impact of the control of leukocyte adhesions to endothelial cells. We will describe the role played by anti-oxidants in reducing the impact of lipid peroxidation on the cascade of inflammatory reactions. We will finally present some interesting technologies aimed at the control of phosphodiesterase to increase cAMP levels in monocytes. To conclude this review, we will look at the correlation between each of these variables and the clinical signs of skin sensitivity. We will review the effect of various anti-infiammatories, phodiesterase inhibitors, adhesion inhibitors, and anti-oxidants on the clinical manifestation of sensitive skin. Conclusion: Due to the complexity of the sensitive skin reactions, it becomes obvious that only a multi-faceted therapy will be able to control this condition. The understanding of the etiology of sensitive skin, as well as the development of cosmetic products based on the technologies described in this review, allows us not only to provide relief to those consumers experiencing regularly sensitive skin reactions, but in addition, to create products which are perfectly compatible with a large variety of skin conditions. EXPLORING THE RELATIONSHIP BETWEEN FACIAL SEBUM LEVEL AND MOISTURE CONTENT Louis B. Fisher Ph.D. Mary Kay Holding Corporation A common perception is that a direct relationship exists between sebum and moisture content, implying that scbum may somehow moisturizc the skin, maybe by preventing water loss. To test the accuracy of this concept, a group of 60 women was studied aged from 20 to 60. They wcrc asked to cleanse their faces using their normal procedure prior to coming to the laboratory, but apply no other product, including moisturizcrs, facial makeup, sunscreens, etc. Two to three hours after cleansing, individuals wcrc cquilibrated to 20øC and 40% RH for 15 minutes. Four sites (forehead, cheeks, jawline and chin) on the face were evaluated for moisture (Novameter TM) and oil levels (Scbumetcr•). A notation was also made of the person's opinion as to their own skin type, showing a distribution of 35 people with normal to oily skin 12 with normal to dry skin 6 with normal skin and 7 with oily/dry combination skin. Combining data from all individuals resulted in remarkably little variation being seen across the face in terms of moisture (120.05 + 5.9), although there was some suggestion of a t-zone distribution, particularly in certain individuals. In contrast, a clear-cut t-zone distribution resulting in a large variation across the face was seen for scbum values (65.7 + 44.4). It was also apparent that the moisture level found in the different groups was very similar (fig.'s 1-4). In other words the individual's perception of dryness did not seem to be reflected by differences in instrumental measurements.