Irritant reactions reflect a damaging effect of the cosmetic or toiletry on the skin – an example would be the effect of too much soap or shampoo on the skin leading to chapping, dryness and soreness. Delicate areas of the body where the skin is naturally thinner such as the skin folds, face, and particularly the eyelids are most vulnerable to irritant reactions. Other sorts of cosmetic which can cause irritation include liquid foundation, mascaras, face masks, toners and anti-ageing creams. Some people suffer from a particularly sensitive skin and experience itching, burning or stinging within minutes of using a product. This is usually a form of irritation rather than allergy and is commoner in people with skin complaints such as rosacea and dermatitis. It may help to use products that say they are for use on sensitive skin as the manufacturer will usually have undertaken further testing to reduce the risk of a reaction occurring. It may, however, be a matter of trial and error to find products that are tolerated.
Allergic reactions involve the body’s immune system which is meant to fight against infections, but occasionally get the wrong target – in this case an ingredient of the cosmetic. In order to develop an allergy, you have to be exposed to the allergen more than once, and usually repeatedly. This means that you can become allergic to something which you have been using for a long time without problem. What triggers the allergy process is unclear, but once developed, allergies like this are usually life-long. Allergic contact dermatitis/eczema appears as itchy, sore, red bumpy skin, which becomes flaky and dry. If you avoid further contact with the allergen, it should improve within a week or so. It is worst where the product has been applied to the skin but can sometimes spread to other parts of the body. Treatment with a topical steroid cream will help to clear the rash more quickly.
Allergic contact dermatitis is an example of a delayed-type allergy and the reaction may not appear until several hours or even days after using the product. This makes it difficult to work out what has caused the problem.
Patch testing can help to identify chemicals in cosmetics that your skin has become allergic to. It involves applying small amounts of allergen to the upper back and observing the skin’s reaction over several days. This sort of test is usually performed in hospital by a dermatologist. When the allergen has been identified, it should be possible to avoid future contact with it in cosmetics and toiletries as the European Union has passed regulations that require a full list of ingredients to be included on the packaging or container.
A simple method to find out if you could have a reaction to a cosmetic is to apply it to a 50 pence sized area of skin on your elbow crease every morning and night for up to a week. This type of test should not be done with things that you would usually wash off such as shampoos or shower gels, as these will simply irritate the skin. If redness and small bumps appear, it suggests you may be allergic to something the product. Patch tests are then important to pin point which substance or substances in the product are causing the reaction so that you can avoid them in other products as well.
The most common ingredients in cosmetics which cause allergic reactions are fragrances and preservatives. There are many different types of fragrance ingredient but you can tell if a product has a fragrance added as it will include ‘parfum’ in the ingredient labelling.
The most common ingredients in cosmetics which cause allergic reactions are fragrances and preservatives. There are many different types of fragrance ingredient but you can tell if a product has a fragrance added as it will include ‘parfum’ in the ingredient labelling.
If you are allergic to fragrance, you may also need to avoid fragranced plant extracts that may be labelled separately with the Latin name. Plant extracts which may cause allergic reactions include tea tree oil, citrus extracts, lavender etc.
Preservative chemicals are needed in most cosmetics and toiletries to stop them degrading and becoming contaminated by bacteria. They often have long names e.g. imidazolidinyl urea, quaternium 15, methylisothiazolinone etc.
Other things which occasionally cause allergic reactions include nail varnish resin (particularly acrylate nails) and sunscreens.
Do not be misled by the description of products as ‘hypoallergenic’ or ‘natural’, as these can contain a variety of common allergens.
Hair dye is another common cause of allergic contact dermatitis and this is almost always caused by phenylene diamine chemicals. Strong allergic reactions can develop causing a lot of swelling and redness of the ears, face and neck as well as the scalp. This sort of allergy often affects people who have coloured their hair for years without any problem. As phenylene diamines are present in all permanent and semi-permanent hair dyes, it may prevent you colouring your hair again in the future. Natural substances such as pure henna and indigo are safe. BUT beware that black henna (used for temporary tattoos around the Mediterranean) contains phenylene diamine and frequently causes allergic reactions in children.
The management of suspected contact dermatitis involves temporarily stopping use of all cosmetics on the affected area and treating the skin with a steroid cream. A soap substitute such as emulsifying ointment or aqueous cream can be used instead of soap for washing and also left on the skin as a moisturiser. In most cases, a mild steroid is all that will be needed, and these can be bought from a pharmacist without prescription, but more severe reactions require medical attention and may need treatment with a short course of steroid tablets. When the reaction has settled, patch testing should be performed by a skin specialist in order to correctly identify the allergen, and minimise the chance of suffering another attack from the chemical in another product.
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