Xerosis is dry desiccated skin. Such skin is unable to fully control its barrier function and loses its pliability. It is vulnerable yet responsive to the use of emollients in aiding relief and helping recovery. Control of transepidermal water loss, using emollients and consequent switching off of the skin’s repair mode such as the release of cytokines and its call for neutrophils, is a basic mission for every carer of the skin. In support of their water initiative, Procter and Gamble are giving away Glycerol, a known ideal emollient. This ‘miracle’, an emollient applied as a first principle for the maintenance of the health of the skin and often to cure it of its sickness, has a rational scientific basis for such claims, justifying its promotion as the subject of the ‘First Commandment’ in Dermatology.
Warning The slightest breach of the epidermal barrier places the epidermal factory in repair mode. It is only during the last decade that the full picture of the activated epidermis has been seen to be more than just the release of histamine and the production of prostaglandins. It now includes interleukins, interferons, tissue necrosis factors as well as growth factors such as Vascular Endothelial Growth Factor (VEGF). These are rapidly produced in the epidermis to flood the dermis and activate the blood vascular endothelium – to bring into play the white cells and macrophages for elimination of the undesirable and for repair.
Contemporary technology can breed mice without essential components for the epidermal factory. This has confirmed that when the barrier is broken, the cytokine production is switched on and when repair is complete they are no longer manufactured. Probably the epidermis first knows that its barrier is breached when transepidermal water flows faster and is lost from the surface.
Action Such flow and loss can be instantly slowed down by placing an artificial barrier on the skin surface such as an emollient, petrolatum, honey or a covering of polythene or hydrocolloid dressing.