Morphometric computerized analysis as a method to assess skin atrophy caused by corticosteroids.

We have employed morphometric computerized analysis to quantify changes in atrophic skin. Atrophy was induced on volunteers by means of the Duhring chamber assay, using two commercial corticosteroids with a steroid-free base as control. After 20 days, atrophy was assessed by subjective examination and rated on a five-point scale. After 10 and 20 days, positive replicas of the areas under test were obtained. Photographic reproductions of these replicas were stored in the image memory of an interactive automatic computerized image analysis system, Kontron Zeiss Ibas 2, and processed with a suitable program. After selection of the measurement area by means of a circular measurement window, the 'continuous tone' image was converted to a 'binary' one by means of a dynamic discrimination function, in order to perform an automatic evaluation of the percentage area corresponding to the shadows cast by the surface markings. Morphometric computerized analysis proved to be a sensitive method for quantifying skin atrophy. A high degree of correspondence with subjective examination was shown. The method allows an objective differentiation between a mid-potency and a high-potency topical corticosteroid.