EMC - Dermatologie-Cosmétologie最新文献

The aim of this presentation is to provide practitioners with an update on the development of knowledge concerning the pathogenesis and treatment of acne from 1991 to 2001. This report reflects the best data available at the time the report was prepared, but caution should be exercised in interpreting the data; the results of future studies may induce modified conclusions or recommendations set forth in this report.

Hepatobiliary and pancreatic affections may result in numerous cutaneous manifestations; these have often an indication value that makes them highly interesting for the dermatologist. Their frequency is variable and, in some of them, the evolution is progressive. The frequency of combined hepatitis B + disseminated necrotizing periarteritis which was estimated to be from 30% to 45% has been lowered to about 7% as a result of vaccination campaigns. Conversely, the frequency of the affections related to hepatitis C, in particular cryoglobulinaemia-induced angeitis, has increased. In France, hepatitis C seroprevalence is close to 1%, which indicates 500,000 to 600,000 infected individuals. However, over a half of them are not aware of such seropositivity, which contributes to virus dissemination, particularly in drug-addicted populations. Alcoholic cirrhosis induces numerous dermatologic signs well known by hepatologists. However, the frequently associated isolated or combined deficiency syndromes may be disconcerting, such as the pseudo-glucagonoma syndrome that is observed in severe zinc deficiency. The cutaneous signs observed with other types of cirrhoses are of later occurrence, except for the pruritus related to the primitive biliary cirrhosis that precedes cholestatic jaundice. In pancreatic diseases, cutaneous manifestations are common and, most of the time, indicative. Some of them are frequent but they are observed most of the time by surgeons and gastroenterologists; this is the case with the subcutaneous haemorrhage related to severe acute pancreatitis. Others, such as the panniculites and paraneoplastic syndromes, are rare but have to be detected. This is why a close collaboration between organ specialists is necessary, for the affections of the digestive tract as well as for the liver and pancreas diseases.

Anaesthesia has to be carried-out prior to any dermatological surgery procedure. Local anaesthesia is the major anaesthetic method in dermatology. Topical anaesthesia, local infiltration and loco-regional anaesthesia of the face, fingers and toes as well as tumescent anaesthesia are performed by the operator. In some cases, other anaesthetic procedures may be useful: sedation, general anaesthesia. Nitrous oxygen analgesia may be a new approach in the future.

Resurfacing by CO₂ or Er:YAG laser techniques in the treatment of facial rhytids has traditionally involved ablative methods with, however, associated complications and limitations due to the epidermis “sacrifice”. Recently, rhytid improvement and dermal remodelling have been observed, with the utilization of non-ablative approaches. The underlying principle of non-ablative laser remodelling is to induce a controlled injury to the collagen in the dermis, while completely sparing the epidermis from damage. As dermal collagen heals and remodels under an undamaged outer layer, the skin tightens and smoothes, thus improving it’s appearance. Two classes of lasers are used for non-ablative laser remodelling : i) visible light lasers, including green and yellow light lasers adapted or modified from their original use as treatments for vascular lesions. 532nm (green) and 585nm (yellow) light are strongly absorbed by oxyhemoglobin and melanin in the epidermis and upper dermis. The heating effect in these skin layers triggers the release of various growth factors that stimulate collagen remodelling and tightening. ii) infrared lasers, emitting at 980nm, 1320nm, 1450nm and 1540nm produce invisible light that is absorbed by primarily by water, which heats the superficial layers of the skin. These lasers use contact or non-contact skin cooling to limit the heating effect to the dermis, creating a controlled injury to the dermal collagen, with subsequent remodelling and tightening. More recently, non-ablative photorejuvenation with intense pulsed light (IPL) has been introduced. Several clinical studies on non-ablative lasers, using objective evaluations (silicone imprints, cutometer, ultrasound imaging) have clearly demonstrated a progressive improvement over months. Histological examinations of the treated areas have clearly showed a superficial dermal band of well organized elastin and collagen fibres replacing pre-treatment elastic tissue. This improvement of the skin was not associated with any adverse effects. Concerning intense pulsed light, only a few clinical studies have reported varied clinical results with non-ablative photorejuvenation.

In relation with the creation of the European Union, European regulatory guidelines have been elaborated to unify and harmonize the legislation of the different states concerning cosmetic development, i.e., the definition, labelling and composition of cosmetic products. The points which remain to be actualised are the guidelines for product elaboration, animal experimentation and post-marketing cosmeto-vigilance. The regulation fixed by the original guideline 76/768/CEE evolves continuously in relation with the evolution of scientific data, and a close collaboration between political institutions, consumers and industrials.