D. Schmid, F. Suter, F. Zülli
SÖFW-Journal 131 (11): 14 - 18 (2005)
Sensitive skin tends to be more susceptible to some environmental factors. People with sensitive skin report exaggerated reactions such as redness, itching or rashes when their skin is in contact with certain cosmetics, plants or fabrics, hot or cold, or insect bites. Normally, people with sensitive skin show quicker an erythemal reaction against ultraviolet irradiation. Skin that is sensitive to sun, typically shows allergic reactions, induced by ultraviolet radiation alone or in combination with chemical ingredients in skin care products. The most important factors for sensitive skin are skin dryness and atopic skin, means skin that is hyper reacting towards allergens.
This article describes a preparation of the Opuntia cactus that helps against sensitive skin in two different ways: it increases skin hydration and it specifically reduces the itch sensation and local inflammation. The latter phenomena are the consequence of a “crosstalk” between the stratum corneum, free sensory afferent nerve endings and mast cells. A stimulus such as a pruritogenic substance or inflammatory mediators or cytokines produced by keratinocytes act either directly on a subset of specialized nerve endings, called C-fibers, inducing an action potential or on mast cells inducing degranulation. The action potential leads to the evocation of nociceptive reflexes and pain behaviour and to the re-lease of neuropeptides such as substance P and the calcitonin gene-related peptide (CGRP). These neuropeptides induce dilation of the surrounding capillaries and local inflammation and also degranulation of mast cells. Degranulation liberates histamine, which, in turn, initiates itch and local inflammation by stimulation the C-fiber nerve endings.
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An Opuntia Cactus Extract to Treat Sensitive and Dry Skin
D. Schmid, F. Suter, F. Zülli
CosmeticsDesign Europe & .Com (05/2007)
The pads of the cactus Opuntia are known as nopales and are used in Mexico as dietary supplement to promote weight loss and as medicine to treat inflammation and pain. Purified components of the Opuntia cactus were used for the development of a cosmetic ingredient that provides long-lasting hydration to skin even in rinse-off applications. This ingredient has also remarkable soothing properties which could be shown in a fascinating cell culture system with nerve cells. The Opuntia cactus ingredient was found to inhibit the depolarisation of sensory nerve cells upon stress. The ingredient can be used in sun care products and skin care products to soothe sensitive and dry skin.
