A Review of Anti-Irritants, Part I: Barrier Cream Efficacy on Contact Dermatitis*

By: Howard I. Maibach, MD, University of California School of Medicine; and Hongbo Zhai, MD, University of California

Posted: March 2, 2011, from the March 2011 issue of Cosmetics & Toiletries.

page 4 of 8

Tannic acid barrier protection: Shimizu and Maibach evaluated the barrier protectant tannic acid on human subjects utilizing squamometry. Either 5% tannic acid or distilled water (control) were applied to the forearms of subjects for 30 min; these pretreated sites were then dosed with 0.25%, 0.5% or 1% of SLS for 24 hr. Squamometric evaluation indicated that skin damage increased with SLS concentration in a dose-dependent manner, and tannic acid significantly reduced the damage.

Dimethicone/glycerin skin protectant: Patterson et al. determined the preventive effect of a skin protectant containing dimethicone and glycerin with various inactive ingredients in an aerosol foam against SLS-induced ICD and urushiol-induced ACD (poison ivy and poison oak). Skin reaction was assessed periodically for 10 days using a 0–7 point dermatitis scale. The formulation was significantly effective in reducing SLS irritation but did not prevent urushiol-ACD.

Hydrogel vs. petrolatum cream: Draelos conducted a randomized, double-blind, split-body study in a total of 80 men, women and children between the ages of newborn and 80 with the following dermatological conditions: household dermatitis, occupational hand dermatitis, latex glove-induced ICD, diaper dermatitis, cutaneous wounds and ACD. The subjects were given two identical jars—one containing a petrolatum-based cream and the other, a hydrogel-based barrier repair cream—and were instructed to apply one cream to half of their bodies and the other cream to the other half for four weeks. Both subject and investigator assessments were recorded by questionnaire. The hydrogel barrier/repair cream showed better skin improvement than the petrolatum-based cream in both subject assessment and investigator assessment.

Dimethicone ICD protection: Zhai et al. evaluated the efficacy of a dimethicone skin protectant lotion against SLS-induced ICD in humans with clinical visual grading and bioengineering techniques. Both forearms were pretreated either with the protectant test lotion or with its vehicle control prior to contact with SLS. After 30 min, 0.5% SLS was applied to each pretreated site for 24 hr. One additional site received SLS only. The protective effect of the dimethicone-lotion was determined by visual scoring (VS), TEWL measurement, skin color (a* value) and cutaneous blood flow volume (BFV). VS and TEWL data showed a significant decrease on the lotion-pretreated site in comparison with the SLS-treated site and the vehicle control site. However, BFV and a* values did not show a statistical difference between treated sites.

BC protection for hospital use: Berndt et al. investigated the efficacy of a BC and its vehicle in a field setting: two panels of 25 hospital nurses with mild signs of skin irritation were instructed to use one of the test products, BC or its vehicle, before contact with skin irritants over the course of four weeks. Effects of both preparations were studied weekly by clinical examination and bio- engineering measurements. Results showed no significant differences between BC and its vehicle. In both groups, clinical skin status improved and stratum corneum hydration increased significantly. Researchers concluded that the vehicle alone was capable of positively influencing skin status.