Non-invasive methods are very useful for quantifying the atrophogenicity of topical corticosteroids.

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.

Lipids of the stratum corneum are implicated in cohesion and desquamation of the stratum corneum as well as in the maintenance of normal barrier function. Evidence linking the intercellular lipids to such processes has mainly been derived from studies on acquired or inherited diseases of lipid metabolism manifesting abnormalities in the structure and the function of the stratum corneum. We have studied the composition of stratum corneum lipids in clinically normal individuals with typical xerosis or ‘winter dry skin’ in order to establish if the lipid composition differs from that of normal individuals, showing no signs of xerosis. The amount of total stratum corneum lipids was not related to xerosis (22.0 ± 1.8 μg/cm² for normal skin, and 26.3 ± 2.9 μg/cm² for severe xerosis), and no correlation was evident between polar lipids, cholesterol sulfate (2.8 ± 0.5% for normal skin, and 1.6 ± 0.2% for severe xerosis), or ceramides types I-VI, and dry skin. It therefore appears that dramatic changes in stratum corneum lipids are not detectable in normal ‘winter dry’ skin. However, a decreased proportion of neutral lipids (sterol esters, triglycerides), coupled to increased amounts of free fatty acids were found associated to the severity of dry skin. Apart from a decline in the sebaceous function and in esterases activity, winter dry skin does not appear to be associated to dramatic changes in polar stratum corneum lipids.

Pretreatment of skin with all-trans retinoic acid (tretinoin) has been shown to enhance wound healing. Previous studies have mainly used animal models to demonstrate this effect. We wanted to determine whether pretreatment could promote wound healing in severely photoaged dorsal forearm skin. Four elderly men with severely actinically damaged forearms were treated daily for 16 weeks. One arm was treated with 0.05-0.1% tretinoin cream (Retin A, Ortho), and the other with Purpose cream (Ortho) as a vehicle control. Four-millimetre punch biopsies were taken from both dorsal forearms prior to treatment. After 16 weeks, full-thickness 2-mm punch biopsies were taken from both sides. Serial photographs were taken, and healing of the wounds quantitatively assessed by image analysis. On the 11th day, the wounds were excised using a 4-mm biopsy punch. Biopsies were processed for light microscopy. After 16 weeks, the tretinoin-treated forearms showed moderate erythema and scaling. Polarized light photographs revealed multiple, red, vascularized foci and/or a diffuse network of small vessels. The histological effects were typical for tretinoin, i.e. compaction of the stratum corneum, epidermal acanthosis with correction of atypia, an increase in small vessels, and increased cellularity in the upper dermis. Purpose cream had no effect, either clinically or histologically. On the tretinoin-treated side, the wound areas were 35-37% smaller on days 1 and 4, and 47-50% smaller on days 6, 8, 11, compared with the controls. Clinically and histologically, reepithelialization occurred more rapidly. Thus tretinoin dramatically accelerated wound healing in photodamaged skin.