AGE-RELATED DIURNAL CHANGES OF DERMAL EDEMA - EVALUATION BY HIGH-FREQUENCY ULTRASOUND

Using high-frequency ultrasound, we measured the influence of gravitat ional stress on skin echogenicity in 22 young (age range 17-27; median 19) and 22 elderly (age range 75-100; median 87) healthy adults. B-mo de ultrasound images were obtained from the medial malleolus, lateral calf, anterior thigh, volar forearm and the medial aspect of the arm t hree times daily: in the morning, immediately before rising, and 2 and 12h later. The echogenicity was measured by counting the number of lo w echogenic pixels in the image. Pronounced changes of low echogenic p ixel numbers were seen in the areas exposed to high gravitational stre ss, i.e. the ankle and calf. In the young age-group echogenicity of th e skin increased steadily during the day, whereas in the elderly popul ation echogenicity decreased 2h after getting up in the morning, and s ubsequently returned to the baseline level. In a control group of 10 p eople (aged 17-83; median 18), who remained in the supine position thr oughout the day, the echogenicity of the skin remained unchanged. As t he echogenicity of the dermis is inversely related to the amount of fl uid it contains, our results indicate that young skin responds to grav itational stress by fluid depletion. In the skin of the elderly, the m echanism of fluid removal appears to be defective. The impaired protec tion against the development of intradermal oedema in the elderly may predispose to the development of lipodermatosclerosis and leg ulcerati on.