A bioengineering study on the efficacy of a skin protectant lotion in preventing SLS-induced dermatitis.
BACKGROUND/AIMS: This study evaluated the efficacy of a dimethicone skin protectant lotion against sodium lauryl sulfate (SLS)-induced irritant contact dermatitis (ICD) by clinical visual grading and bioengineering techniques in 12 healthy humans. METHODS: The flexor aspects of both forearms of the subjects were used as test sites. Each test was duplicated to diminish the variations of the test sites. In a random order and a double-blind manner, two test sites were pretreated either with the testing protectant lotion or with its vehicle control prior to contact with SLS. Thirty minutes later, 0.2 ml of 0.5% SLS in a polypropylene chamber was applied to each pretreated site. One additional test site served as a positive control (without lotion), receiving the irritant only. After 24 h of exposure to the irritant, the chambers were removed. The efficacy of protective effect was determined by four parameters: visual scoring (VS), transepidermal water loss (TEWL), skin color (a* value), and cutaneous blood flow volume (BFV). All test sites were assessed with the parameters daily for 5 days. RESULTS: The VS data showed a significant decrease on the site pretreated with protectant lotion in comparison with the SLS-only treated site (P<0.01) and with the site pretreated with control vehicle (P<0.05) (overall for 5 days). TEWL value was significantly decreased in comparison with the SLS-only treated site (P=0.02 at day 2; P=0.008 at day 4; P=0.014 at day 5) and with the site pretreated with the control vehicle (P<0.05) (day 2, 4 and 5). However, the BFV and a* values did not show a statistical difference between protectant lotion, vehicle, and SLS-only treated sites. CONCLUSIONS: This study demonstrated that appropriate dimethicone skin protection products may provide certain benefits from surfactant ICD. The skin protectant lotion may be used to prevent ICD in home or work environments, where skin irritants may induce dermatitis or eczema.