Dermal oedema in lipodermatosclerosis: distribution, effects of posture and compressive theraphy evaluated by high-frequency ultrasonography.

Although leg oedema is believed to contribute to the pathogenesis of lipodermatosclerosis and leg ulcer, little is known about the cutaneous distribution of water in lipodermatosclerosis. In lipodermatosclerosis accompanied by leg ulceration, a subepidermal low echogenic band is seen in the high-frequency echograms of the skin at the boundary of the wound. Since skin echogenicity is inversely related to the amount of water contained, it has been assumed that the subepidermal low echogenic band corresponds to oedema in the papillary dermis. In this study we evaluated dermal oedema in lipodermatosclerosis by quantifying changes of skin echogenicity in 20 patients with lipodermatosclerosis and 20 age- and sex-matched controls. In order for us to evaluate the influence of the upright posture on skin water content, echogenicity was determined three times a day in various regions of the lower and upper extremities. Next morning, after ultrasound examination of the ankle skin, a compressive stocking was applied for 12 h and then the measurements of echogenicity were repeated. At any time of the day, ankle and calf skin was less echogenic in lipodermatosclerosis than in the control. The low echogenic area was confined to the subepidermal region. During the day the low echogenic area expanded in patients with lipodermatosclerosis. This phenomenon was reversed by leg compression. These results indicate that in lipodermatosclerosis oedema is located mainly in the papillary skin. An upright position causes aggravation of oedema, whereas application of compression protects against accumulation of water in the skin during the day.