Moisturizers for contact dermatitis

OB/GYN News, Jan 15, 2005 by Robert Finn

SANTA FE, N.M. -- Despite the widespread use of topical corticosteroids for irritant contact dermatitis, there is little evidence that they work any better than moisturizers, and they may make the dermatitis worse, Howard I. Maibach, M.D., said at a dermatology conference sponsored by the Skin Disease Education Foundation.

"Since the corticosteroids became available in the late 1950s, all dermatologists in all countries that I've visited simply say, 'Treat irritant dermatitis with cortico steroids,'" said Dr. Maibach of the University of California, San Francisco. "There are a handful of experiments now, and they are all universally clear. The corticoids either make it worse or don't help."

Several of those experiments came from Dr. Maibach's laboratory, conducted by Cheryl Levin, now a medical student at Stanford (Calif.) University.

In one experiment, six subjects had their hands irritated by repeated handwashing with sodium laurel sulfate (SLS), an ingredient in many detergents. In a double-blind fashion, small areas on the dorsal side of each volunteer's hands were treated with carefully measured doses of 0.1% betamethasone 17-valerate ointment, 1% hydrocortisone ointment, and petrolatum as a vehicle control (Skin Res. Technol. 2001;7:214-8).

The subjects were treated once on the first day and twice a day on days 2-5. While SLS induced significant changes in transepidermal water loss (TEWL) and squamometry, there were no significant differences among any of the treatments at any time point.

In a second experiment, 11 healthy volunteers had dorsal areas of their hands irritated by 90% and 60% nonanoic acid, a naturally occurring lipophilic fatty acid, which was applied on an adhesive patch and left on for 24 hours. All subjects were treated in a double-blind fashion with betamethasone, hydrocortisone, or vehicle (Exog. Dermatol. 2002;1:97-101).

At a single time point--day 8--the areas treated with betamethasone were slightly but significantly better, compared with control areas when measured by TEWL. On day 3, areas treated with the vehicle control proved to be significantly better when measured by laser Doppler flowmetry. These differences, though statistically significant, were quite small, and the authors questioned their clinical significance.

Other studies in other laboratories are beginning to show that certain moisturizers appear to be more effective than corticosteroids in treating irritant contact dermatitis. "I think you really ought to look at those patients and ask whether you're helping them or harming them with topical corticosteroids," Dr. Maibach said.

The SDEF and this newspaper are wholly owned subsidiaries of Elsevier.

BY ROBERT FINN

San Francisco Bureau