In order to identify and characterize the sonographic variations between different age groups, 48 subjects, 24 aged 27–30, and 24 over 60, were studied with a 20-MHz B scanner on six skin sites. Images were evaluated by the instrument’s standard programme and by a new image analysis software package enabling the characterization of steady structures or transitory functional aspects of skin reactions, by highlighting areas in which the echo amplitudes are included within selected values, and by calculating their extension. Three bands were selected as intervals of interest, respectively, highlighting hyporeflecting parts of the dermis, tissue reflecting with intermediate amplitude values and hyperreflecting epidermis and dermis. This method was employed to assess skin thickness, demonstrating its decrease in elderly skin, to characterize and quantify the hypo-echogenic subepidermal band appearing in the elderly at volar and dorsal forearm skin, and to evaluate echogenicity of the upper and lower dermis. Our data show that there is a great regional variation in the behaviour of ultrasound reflection of elderly skin in respect to the skin of young subjects. However, a general trend can be identified, consisting in a shift from low-intensity ultrasound echoes, characteristic in the dermis of young subjects, to intermediate or high reflection amplitudes, which are more frequent in elderly skin. Thus, the echographic method provides two parameters for the evaluation of skin aging. Besides an accurate and early assessment of skin atrophy, it also enables an evaluation of physical properties of the skin, which do not influence the morphological aspect in microscopy, but induce variations of the acoustic behavior which are expressed by a modification ofthe reflectivity to ultrasound.

The density of follicles on various regions of the human face has received scant attention. We used cyanoacrylate follicular biopsies to determine the number of follicles on the forehead, cheek, chin and nose of 12 healthy adult white women. Sebum output was assessed on the same regions by means of Sebutape. The density of follicles and sebum output followed a centrolateral decreasing gradient. There was no correlation between these two parameters. These regional patterns are important for studies of the pathogenesis of common disorders of the face and their response to treatment.

Background/alms: Optical coherence tomography is a new in vivo imaging tool originally developed to investigate the eye. We undertook a preliminary investigation of experimental and clinical dermatological applications. Methods: We obtained optical coherence tomography images of ethnic groups, of cutaneous changes induced by exposure to water and dimethyl sulfoxide, of corticosteroid atrophy and of acne vulgaris. Results: Optical coherence tomography was able to visualize specific structural changes in stratum corneum and viable epidermis in these diverse conditions. Conclusions: The high lateral and axial resolution of 4 urn and 7 μm, respectively, and the image quality of this prototype make optical coherence tomography a promising instrument for clinical and investigative dermatology.

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