This study presents the detailed construction and the principle of performance of high frequency (HF) ultrasound scanner for skin examination. The aim of this study was to show a difference between diseased and healthy skin and to evaluate the usefulness of the scanner in monitoring of therapeutic efficacy of morphea and lichen sclerosus et atrophicus (LSA). We examined 48 patients aged between 15 and 64 years; 25 patients with plaque-type morphea, nine patients with linear morphea and 14 patients with LSA. In the course of 18 months all patients were examined before, during and after treatment. In 29 patients ultrasonographic evidence of regression (decreasing of the skin thickness) was observed, in eight patients ultrasound examination showed progression and in 12 patients no difference in the ultrasound scan before and after treatment could be shown. Our study shows that HF ultrasound scanner is suitable to differentiate between the healthy and diseased skin in morphea and LSA as well as to evaluate the treatment efficacy of these diseases.