PARALLEL INTRAINDIVIDUAL EVALUATION OF THE VASOCONSTRICTORY ACTION AND THE ANTIALLERGIC ACTIVITY OF TOPICAL CORTICOSTEROIDS

The human skin blanching assay is a well established method for rankin g the efficacy of corticosteroids after epicutaneous application. Vaso constriction is a pharmacological activity, which correlates well with the clinical efficacy, the intensity of skin blanching after a single application under occlusion corresponding, generally, to the clinical efficacy after repeated application without occlusion. However, in st udies dealing with the comparison between the vasoconstriction assay a nd the evaluation of the clinical effects on inflammatory skin disease s, some exceptions to this correlation have been reported. Therefore, in a preclinical phase, it would be useful to combine the blanching as say with at least one anti-inflammatory assay. In the present study th e blanching assay and the allergic contact dermatitis inhibition test were performed in parallel, in order to compare the two testing proced ures in the same group of subjects, utilizing standardized study desig ns supported by objective means of evaluation. Three commercial prepar ations of corticosteroids containing clobetasol propionate (CP), clobe tasone butyrate (CB) and hydrocortisone acetate (HA), respectively, we re employed both to treat nickel-induced positive patch test responses on the volar forearms, and to perform a vasoconstrictor assay on norm al forearm skin in 16 nickel-sensitized healthy volunteers. For evalua ting skin blanching, we employed colorimetric measurements, whereas fo r the quantitative determination of the inhibition of the intensity of allergic patch test reactions, 20 MHz B-scanning supported by image a nalysis was used. Both colorimetric and echogenicity values enabled us to distinguish between the three corticosteroids (at the 17 h evaluat ion and the 64 h assessment, respectively). A fair correlation was not ed between colorimetric and echogenicity values. Both testing procedur es ranked the three corticosteroids in the expected order. Corticoster oid preparations should be compared using methods which allow differen t effects to be simultaneously monitored, without involving a high num ber of patients. We are proposing this double procedure for the parall el intraindividual evaluation of the vasoconstrictory action and the a nti-allergic activity of topical steroids.