Contact dermatitis and cosmetics
Cosmetic products can sometimes trigger an adverse response, either irritant or allergic. Alex Gazzola looks at the kinds of responses cosmetics can cause, how to get diagnosed if you have a problem, and how to avoid your triggers.
We use cosmetics to make us look, feel and be healthier, but when the skin appears to react to a product, it is worrying.
Dermatitis is the general term used for any form of inflammation of the skin causing itchiness, dryness, redness and, over time, possibly cracking and coarseness. When this is caused by something coming into direct contact with your skin, such as a cosmetic, chemical, plant, or item of clothing, it is called contact dermatitis. What is hard to know is whether the problem is a genuine allergy or a mere irritation?
Irritant versus allergic
In all, there are four kinds of contact dermatitis and all four are more common in people who have other allergies (food allergy, eczema, asthma, hay fever) or problem skin conditions (such as psoriasis).
Irritant contact dermatitis is the most common type, accounting for 80% of cases. It does not involve the immune system so is not an allergy.
It can be acute (a quick inflammatory response, within hours or even minutes of contact, with symptoms of blistering or a burning sensation) or chronic (a delayed response which can take days or months to develop, eventually resulting in thickened, scaly and dry skin).
Possible irritants include detergents and solvents which strip the skin of its protective oils making it more vulnerable and sensitive. It is common amongst people working with chemicals – cleaners, hairdressers, gardeners etc. The reactions usually become milder with ongoing use or exposure.
Allergic contact dermatitis is less common, and its reactions usually worsen with increased exposure to the allergen. It is a delayed type IV allergic reaction, occurring between 24 and 72 hours after exposure, caused by chemicals such as perfumes or preservatives coming into contact with the skin. Symptoms include blistering, rashes, swelling and reddening at the site of contact.
It is difficult to distinguish the two. Allergic contact dermatitis is more likely to be itchy and localised to the point of contact, while irritant contact dermatitis may be more painful and widespread.
Contact urticaria is a rapid and acute skin reaction, which could be a type I (IgE-mediated) reaction.
(There is also a type of ‘false’ allergy-like reaction which mimics type I contact urticaria and may be experienced by up to 20% of the population. The symptoms are similar, but the immune system is not involved, although histamine release does occur in the skin’s layers. This can be triggered by exercise, pressure on the skin, extremes of temperature and even cold or hot water. Both causes and mechanism are often unknown.)
Photocontact dermatitis triggered by sunlight on a substance (usually sunscreens or fragrances) interacting with the skin; both sunlight and the chemical are required to trigger the reaction. It can be non-allergic, typically producing symptoms like sunburn; or allergic, similar to allergic contact dermatitis described above. Photocontact dermatitis is quite unusual.
Testing and diagnosis
Suspect irritant or allergic contact dermatitis when symptoms ease after weekends or holidays away, when occupational exposures are avoided or changes in routine affect the substances you come into contact with.
The part of the body affected may also suggest contact dermatitis: the face may imply a face cream, the hairline a hair dye, and the armpit a deodorant, for example. However allergens and irritants can easily be transferred around the body – an irritant in nail varnish is transferred when you scratch yourself for example – so the connection is not always obvious.
If your doctor or dermatologist suspects contact dermatitis a full patch-test investigation is warranted. Various test substances are diluted in a base and applied to the skin, usually on the back, and covered. After 48 hours, the covering is removed and the skin examined. Another 48 hours later, it is examined again. During both examinations the scale of any reaction – redness, swelling and blistering – is gauged, scored, and compared.
* An irritant reaction is prominently symptomatic after 48 hours, but resolves noticeably after 96 hours.
If the patch test is uncertain, or to better understand an apparently mild reaction, the Repeat Open Application Test (ROAT) test may be used. This involves applying a suspect chemical or product twice daily to a spot on the forearm for a week to see whether dermatitis results.
Allergic contact urticaria is diagnosed via traditional skin-prick allergy tests.
Photocontact dermatitis is diagnosed in much the same way as ordinary contact dermatitis, but with duplicated patch sets, one of which is irradiated with UVA light after twenty-four hours.
With thousands of potential irritants and allergens used in cosmetics and other products to which we can be exposed, it is impossible to test for them all.
Your dermatologist will probably start with standard tests such as the European Baseline Series, International Standard Series or the British Contact Dermatitis Society (BCDS) Standard Series. Each varies slightly, and the substances included are occasionally revised, but generally they include 30 or so substances and mixes which account for around 85% of all contact dermatitis reactions.
Other occupational chemicals (eg the BCDS hairdressing battery, if you work in this field) may be included, as well as any cosmetic products you use regularly. Specific fragrances and compounds may need to be ordered from laboratories or cosmetic manufacturers and prepared individually.
Several cosmetic ingredients are included in the baseline standards, including formaldehyde, parabens mix, balsam of Peru, and fragrance mixes as well as other extracts which can cause dermatitis via other means of contact – nickel sulphate, to test for nickel allergy from jewellery, for instance.
In the case of contact urticaria, assorted substances (usually including latex, a common allergen) may be tested for via skin pricking.
By an amendment to the EU Cosmetics Directive in 2005, it is now law that the 26 fragrances deemed to be the most allergenic must be named on all cosmetic products and household chemicals when present in concentrations of at least 10 parts per million (leave-on products) or 100 parts per million (rinse-off products / household chemicals). These fragrance compounds must also be named when they form a part of an essential oil included in the ingredients. (16 of the 26 occur naturally in essential oils.) Click here for a list of fragrance allergens.
The list is not without its critics, and many experts have called for its revision. One relatively recent study found that while some of the 26 are common allergens in practice, others are rarely problematic, although could be severe when they do occur.
Balsam of Peru
PPD (PPDA / p-phenylenediamine / paraphenylenediamine)
Lanolin (wool alcohols)
If you are coeliac, you may wish to avoid gluten-grain ingredients, which can be found in creams, shampoos and other products. According to Coeliac UK, there is no risk to coeliacs in using skincare products with wheat in them, but anecdotally many have reported reactions so many choose to avoid them. The Latin for wheat is ‘triticum vulgare’. (For further information, see our article on gluten-free skincare here.)
a/ the names and alternative names / synonyms of your allergens to help you identify them on labelling;
What this boils down to is you will have to carefully read cosmetic labels on cosmetics and, possibly, on food and household products. All cosmetic products sold in the EU must display a complete ingredients list on the product or its packaging. Cosmetics which are small and difficult to label are partially exempt; instead, their ingredients should be displayed close to the point of sale or available on a leaflet.
Ingredients must comply with European law and use the International Nomenclature of Cosmetic Ingredients (INCI) – a standardised form of naming products, used throughout Europe, and in many other countries.
If you have been diagnosed with an allergy to one or more fragrance you may be advised to avoid all fragrances, unless you know the particular fragrance(s) to which you react and can find products which are free from them. In the case of the 26 key fragrance allergens, this can be gleaned from the label, but if you are allergic to others you may need to check with the manufacturer to check whether they are included. Some manufacturers are reluctant to disclose details of formulations, however, so you may have to either resort to trail and error – expensive and frustrating, and risks sensitising you to other fragrances – or else just avoid all. This may be the better option as cross-reactions are always a possibility too.
‘No perfume’ / ‘Unscented’ / ‘Fragrance free’
Preservatives and other allergens
Click here for a useful article on reading cosmetics labelling, written by the International Dermal Institute’s Sally Penford.
Emollients / moisturisers may be all you additionally need to soothe remaining irritation, although you must choose one free of your allergens (many contain lanolin, for instance).
Steroid creams may be advised, as these help reduce inflammation. Mild ones can be bought over the counter, but stronger ones must be prescribed. Again, these creams can contain allergenic ingredients, such as hydrocortisone.
Barrier creams can help reduce contact with an occupational chemical, but their use is controversial, and they can encourage you to take less care with avoidance.
Other products, such as anti-histamines, oral steroids and oral antibiotics, may be advised for particular cases.