Fast itch relief in an experimental model for methylprednisolone aceponate topical corticosteroid activity, based on allergic contact eczema to nickel sulphate

Background Topical corticosteroids (TC) consistently show effectiveness against itch, a paradigmatic symptom, in various eczemas. Rapid itch relief is a therapeutic goal. The early response of itch to TC has not been adequately studied. Objectives To assess the effect on itch of a TC, methylprednisolone aceponate 0.1% ointment (MPA), in induced eczema in volunteers sensitized to nickel sulphate. Methods Sixteen volunteers with a late positive patch-test reaction to nickel sulphate entered the study. Eczema was treated once daily with ¼ fingertip unit of MPA for 5 days. Pruritus intensity was assessed with a 10 cm visual analogue scale (VAS). Mean time to itch relief (TR) defined as the time to reach a 30% decrease in the highest VAS value recorded was assessed, as well as TR-baseline, colorimetry and planimetric morphometry of the reaction. Results Mean TR was 1.0 days [standard deviation (SD) = 1.1] and mean TR-baseline was 1.6 days (SD = 1.4). Five volunteers reached 100% decrease from itch baseline-VAS in 2.0 ± 1.2 days, whereas a 75% decrease was obtained in 1.7 ± 1.6 days by 16 volunteers. A clinical improvement of patch-test reaction was apparent at day 11, although erythema was still present. Conclusion We present a valid model to assess the efficacy and speed of action of TC treatment to alleviate pruritus and the signs of eczema. The fast effect of MPA against pruritus supports the appropriateness of treating allergic contact eczema with TC.