Sensitive Skin, Skin Care Products, and Cosmetics
Skin care and cosmetics used in subjects affected by sensitive skin should be carefully selected in order to have a good compliance and possibly promote skin health. Indeed, sensitive skin has been classified primarily as a local reaction after the application of a cosmetic product (1).
Appropriate skin care includes cleansing, moisturizing, and application UV protection to maintain healthy skin. UV protection consists of sun avoidance, UV-protective clothing, and sunscreens (2). Therefore, effective cleansers for eczema and sensitive skin should provide effective cleansing without compromising the barrier integrity, and cosmetic or therapeutic moisturizers should be indicated as an important adjunct to alleviate dryness of the skin and restore skin barrier function (3).
Washing twice daily with a classic alkaline soap (pH 10.2) reduces the thickness of the SC cell layers, with associated attrition of intercellular lipids causing dryness, desquamation, and barrier damage (4). In diseased skin such as in sensitive or atopic skin, special cleansing agents are recommended consisting of non-soap-based surfactants, synthetic detergents (syndets) with an acidic or neutral pH, and lipid-free cleansing lotions. New formulations also include cleansers restoring intercellular lipids by delivering ceramides or similar lipids after washing (5). In a study of skin irritation of six cleansing agents designed for sensitive skin, 60 patients used a bar and a lipid-free liquid cleanser in a paired-comparison design. Among the users of the bar soaps, 41% of the patients discontinued because of facial erythema. However, there were no discontinuations among patients using the nonsoap cleansing lotion, which was also rated as causing the least irritation (6). Lipid-free cleansing lotions contain fatty alcohols and are designed for sensitive or dry skin; lotion formulations can be removed without water (7). Lipid-free cleansers also contain emollients and/or humectants to cleanse while protecting the skin from moisture loss. The pH of a cleanser is also important; neutral or acid pH cleansers (about 5.5), close to the normal pH of the epidermis, are recommended. It has been suggested that alkaline cleansing agents contribute to the dehydration of the SC and dry skin and should be avoided (8,9). Furthermore, the preventing loss of SC hydration can help in improving barrier performance.
Water alone is not recommended for cleansing. Barrier function is not improved by using water alone without soap because water is a uniphase element and is not immediately absorbed into the skin (3).