Alpha hydroxyacids modulate stratum corneum barrier function.
ABSTRACT Alpha hydroxyacids (AHAs) are used to enhance stratum corneum desquamation and improve skin appearance. The purpose of this study was to evaluate whether some AHAs improve skin barrier function and prevent skin irritation. Eleven healthy subjects (aged 28 +/- 6 years, mean +/- SD) entered the study. Six test sites of 8 x 5 cm (four different AHAs, vehicle only (VE) and untreated control (UNT) were selected and randomly rotated on the volar arm and forearm. The four different AHAs at 8% concentration in base cream were glycolic acid (GA), lactic acid, tartaric acid (TA) and gluconolactone (GLU). The products were applied twice a day for 4 weeks (2 mg/cm2). At week 4, a 5% sodium lauryl sulphate (SLS) challenge patch test was performed under occlusion for 6 h (HillTop chamber, 18 mm wide) on each site. Barrier function and skin irritation were evaluated by means of evaporimetry (Servomed EP-1) and chromametry (a* value, Minolta CR200) weekly, and at 0, 24 and 48 h after SLS patch removal. No significant differences in transepidermal water loss (TEWL) and erythema were observed between the four AHAs at week 4. After SLS challenge, GLU- and TA-treated sites resulted in significantly lower TEWL compared with VE, UNT (P < 0.01) and GA (P < 0.05) both at 24 and 48 h. Similarly, a* values were significantly reduced after irritation in GLU- and TA-treated sites. This study shows that AHAs can modulate stratum corneum barrier function and prevent skin irritation; the effect is not equal for all AHAs, being more marked for the molecules characterized by antioxidant properties.
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ABSTRACT: The categories used to describe skin types have changed little over the last century, whereas the skin care product market has undergone rapid innovation and exponential growth. There are four basic dichotomies or parameters that have recently been introduced in the Baumann Skin Type Indicator (BSTI) that more accurately characterize skin types. By evaluating skin according to these parameters--dry or oily, sensitive or resistant, pigmented or nonpigmented, and wrinkled or unwrinkled--and thus differentiating among the 16 permutations of possible skin types, consumers can more easily identify the most suitable topical treatments for their skin. This article describes the four parameters that make up the BSTI, focusing on basic science and defining characteristics and summarizing the 16 skin-type variations.Dermatologic Clinics 08/2008; 26(3):359-73, vi. · 2.16 Impact Factor
Journal of Cosmetic Dermatology 02/2005; 4(1):44-5. · 0.98 Impact Factor
Article: Fruit acids do not enhance sodium lauryl sulphate-induced cumulative irritant contact dermatitis in vivo.[show abstract] [hide abstract]
ABSTRACT: Combined exposure to different irritants in the workplace may lead to irritant contact dermatitis, which is the main type of occupational dermatitis among bakers and confectioners. Following previous work on "tandem irritation", a panel of healthy volunteers was exposed twice daily for 4 days to the organic fruit acids: citric, malic, and lactic acid, either alone or in tandem application with 0.5% sodium lauryl sulphate (SLS) in a repetitive irritation test. Irritant cutaneous reactions were quantified by visual scoring and non-invasive measurement of transepidermal water loss and skin colour reflectance. Twice daily application of either citric or malic acid alone did not induce a significant irritant reaction. Combined exposure to one of the fruit acids and SLS caused marked barrier disturbance, but the latter irritant effect was smaller than that obtained by combined exposure to SLS and water. Thus, combined exposure to the above-mentioned fruit acids and SLS did not enhance cumulative skin irritation.Acta Dermato Venereologica 02/2005; 85(3):206-10. · 3.18 Impact Factor