Eczema, Skin Conditions | December 6, 2014 | Author: The Super Pharmacist
Sensitive skin is a term often used to describe skin that appears prone to exhibit symptoms in response to exposure to various substances and environmental factors. These include pollution, allergens and chemicals. This last definition may extend to a variety of compounds (e.g. liquids and solids) found in the home, particularly those found in household products and solutions such as detergents, soap and skincare products. These may contain 20 or more ingredients, included for a variety of reasons. These might include:
However, many people may not tolerate these ingredients, and/or find that they easily elicit unwanted effects such as irritation, dryness or redness. In severe cases, an individual may have an intolerance or allergy to these chemicals, resulting in conditions such as dermatitis or hypersensitivities.
Hypersensitivity is a significant increase in natural immune-system or inflammatory molecules, which may be associated with chain reactions in blood and/or cardiovascular system cells.
This may lead to a wide range of symptoms, such as:
In other cases, skincare components may increase the risk of adverse reactions or disorders in people who had not experienced such side-effects before. This is known as sensitisation.
Unfortunately, skin products do not have a history of being monitored as closely by state regulatory bodies as do pharmaceutical products. They are usually scrutinised for toxicity in case of ingestion or other types of exposure that may precede an emergency, but their properties that may be associated with adverse effects are often comparatively neglected.
Therefore, cosmetic and/or skincare companies may define products as 'sensitive skin'-specific while employing a rather liberal interpretation of this term. In general, these are products with some or all of the ingredients found to have an association with skin reactions, hypersensitivity or sensitization, removed or substituted.
Recently, European and American regulatory institutions (e.g. the European Cosmetics Regulation) have taken more of an active role in the surveillance of skin products, with the use of controlled laboratory protocols such as skin patch tests to assess the risks of hypersensitivity and/or skin reaction.
Even so, the labelling rules for some relevant products, such as cosmetics, are not as stringent as for many other consumables under the European regulation system, even if they may contain hazardous materials.
Skincare and cosmetic product review is also conducted by specialist independent bodies, such as the Cosmetic Ingredient Review Expert Panel. These may evaluate the safety and sensitisation potential of many ingredients, including those commonly linked to skin reactions. The more prominent sensitive skin products are listed below:
Skincare products often contain fragrances to enhance their marketability, or even sometimes as a unique selling point.
These compounds are associated with up to 16% of contact dermatitis cases.
Fragrances that may cause hypersensitivity or sensitisation include hydroxyisohexyl 3-cyclohexene carboxaldehyde and natural extracts, such as those derived from plants.
Some other chemicals used as fragrances are of a type called alkyl cyclic ketones. These may also be associated with potential for sensitisation. One of these, acetyl cedrene, may be associated with photosensitisation, or the increased risk of ultraviolet light-related damage. Acetyl cedrene is also associated with rare cases of allergic dermatitis.
Despite these possibilities, the allergic potential of fragrance-enhancing chemicals is often ignored. According to the European regulation system, companies are obliged to provide warnings on no more than 26 chemicals associated with hypersensitivity. Therefore, consumers must be vigilant about finding all of these themselves in ingredient lists. Other chemicals used as fragrances include:
This is a chemical often used as a preservative in many personal care and hygiene applications, particularly face or baby wipes. It may be associated with allergic dermatitis, especially in younger children. Methylisothiazolinone was associated with positive patch tests in 21 of 404 patients in a study of skin allergy clinic data, all of which were associated with cosmetic products. Despite this link, the chemical is found in many products marketed as 'hypoallergenic', 'sensitive' or other variations on these terms.
This is a detergent commonly associated with skin irritation and redness. Sodium lauryl sulphate is often used as a standard in achieving experimental skin irritation in order to test treatments for this condition. Other chemicals, particularly organic solvents, may increase the risk of allergic dermatitis or other types of skin damage.
Some epidemiological studies have found an association between wheat intolerance and reactions from contact exposure to wheat protein derivatives included in skin products. A study of Japanese adults with self-reported wheat intolerance found that use of a facial soap with wheat proteins was significantly associated with allergic reactions to wheat, particularly in those with recent-onset wheat intolerance. Some studies report a similar association between products containing oatmeal or oat-derived substances and hypersensitivity.
However, allergic reaction caused by skin contact and/or absorption is generally rare. A large-scale study of oatmeal patch-tests found that swelling occurred in one of over 2200 subjects.
Chlorhexidine is an ingredient used as an antibacterial or preservative agent in many European cosmetic products. It is associated with hypersensitivity-related symptoms including anaphylaxis, but is usually at acceptable and safe concentrations.
Many 'natural' (or 'botanical') ingredients, or those derived from plants or other organisms in varying degrees of refinement, may have a different structure (manifesting as texture differing from other 'chemical' skincare products) and are therefore more difficult to remove from skin, resulting in mechanical damage. This may result in misleading findings on their actual potential for irritation or sensitisation.
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