Objective Assessment of Topical Anti-Inflammatory Drug Activity on Experimentally Induced Nickel Contact Dermatitis: Comparison between Visual Scoring, Colorimetry, Laser Doppler Velocimetry and Transepidermal Water Loss

Abstract

Four topical anti-inflammatory drugs were investigated for their effect on allergic contact dermatitis. Nickel dermatitis was chosen for its high incidence in European healthy volunteers. Experimental lesions were treated twice daily with two steroids, two non-steroidal anti-inflammatory drugs and a blank base for 4.5 days without occlusion. The influence of treatments was assessed by daily visual grading and one site was left untreated for comparison over the same period. To quantify drug activities objectively, skin colour (colorimetry), skin blood flow (laser Doppler velocimetry) and transepidermal water loss (evaporimetry) were measured before drugs were first applied, then 6 h after the last application. As expected, only Dermoval cream significantly improved the spontaneous clinical evolution in comparison with the other creams (Hydrocortisone Astier à 1 %, Parfenac, indomethacin 2.5% and Skinbase) and the untreated site. Colorimetric parameter a* (redness) and L* (luminance) showed more differences between treatments than the other criteria and a close relationship was obtained between these two parameters and skin blood flow, all three being highly correlated to visual grading. Transepidermal water loss appeared less related to clinical improvement but this parameter could prove helpful for detecting compounds which could be irritant to diseased skin.