Monday, April 4, 2016Ingredient of the month

Cosmetic allergens

© CosmeticOBS-L'Observatoire des Cosmétiques

They are among the cosmetic ingredients most often denounced by the press or consumer organisations for their potential to harm health. They are omnipresent in products of all categories, especially as soon as they contain a perfume. 26 of them are subject to a declaration obligation in the ingredient lists. But are they all to be avoided at all?

Reading time
~ 25 minutes

An allergy is not an insignificant pain. When someone is affected, it can result in very different pathological signs like urticaria, rash, various forms of dermatitis like contact dermatitis, asthma, or even anaphylactic shocks, in the most serious cases.

Allergy mechanisms

Technically, it is a clinical phenomenon related to an inappropriate immune response in the presence of a particular substance called an allergen or antigen.
In other words, the allergy mechanism involves an antigen, a natural or synthetic molecule, which induces the immune response when it gets recognized by antibodies or cells in our immune system.
Antigens are usually proteins, polysaccharides, or their lipid derivatives, but antigen fragments called haptens can also induce an allergy.

As a result, many substances used on a daily basis can be a source of allergy, like certain foods (peanuts, crustaceans, gluten…), the acarids nested in dust, some metals used to make jewellery or coins (chromium, nickel…), and of course, cosmetics. Many of their ingredients actually have a documented allergenic potential, such as certain preservatives, UV-filters, hair colourants, and many perfume components, among others, including essential oils.

Hardly any human being is allergic by birth… most often, we become so, and this involves two phases.

Phase 1: sensitization

This phase can be more or less long depending on the individuals: it corresponds to the period when someone is more or less regularly in contact with a more or less important quantity of a particular substance to which they will become allergic.

It all starts when an allergen comes in contact with the skin, for example via a cosmetic product.
Then, it is carried to the epidermis by a cell called Langerhans cell. It presents the allergen to T-cells, white corpuscles that play an essential role in the immune system.
Once the allergen has been recognized by the T-cells, the two cells are activated and produce mediators, which increases the proliferation of T-cells, which in turn results in the rise of specific T-cells: “memory cells” that recognize the allergen. The individual is now sensitized and can react when these memory T-cells are exposed to the antigen in the blood flow.

This phase is said to be clinically inapparent, which means the individual concerned cannot feel any pain or notice any sign: an allergy is an insidious pathology that develops incognito.
NB: the more we get in contact with an allergenic substance, the more repeated the contacts are, and the more important the quantity of the substances at stake is, the more risk there is for an allergy to get triggered.

Phase 2: elicitation

This phase starts following a new exposure to the substance: when that is one too many. The allergen is applied on the skin. Memory T-cells are activated, which leads to the production of inflammatory mediators and creates the allergic reaction.

There we are: the individual has become allergic. And each time there is a contact with the allergenic substance, the reactions repeat themselves, and they can be a bit of a handicap.

Labelling obligations for cosmetic allergens

We can all become allergic to a particular substance. Still, some of them have a very strong allergenic potential: we now know about strong, moderate, or weak sensitizers… and it is obvious that a strong sensitizer has more risks to trigger an allergy if we are frequently exposed to it, and that it would be wise to limit our contacts with it, while a weak sensitizer will be better and longer tolerated without causing any problem.

It is actually to warn and protect the people sensitized to allergenic molecules that the European Cosmetics Regulation has provided for 26 of them – derived from perfumes, essential oils and/or plant extracts – to be mentioned in the list of ingredients of cosmetic products, if their concentration is higher than 0.01% in rinsed-off products, and higher than 0.001% in leave-on products… … Even if these 26 substances do not all have the same sensitizing potential or the same hazard level for health. Here is a “classification” based on the latest scientific evaluations available.

Weak sensitizers
• Alpha-Isomethyl Ionone
• Amyl Cinnamal
• Anise Alcohol
• Benzyl Alcohol
• Benzyl Benzoate
• Benzyl Salicylate
• Hexyl cinnamal
• Limonene
• Linalool

Moderate sensitizers
• Amylcinnamyl alcohol
• Benzyl Cinnamate
• Citronellol

Strong sensitizers
• Cinnamal
• Cinnamyl Alcohol
• Citral
• Coumarin
• Eugenol
• Farnesol
• Geraniol
• Hydroxycitronellal
• Isoeugenol
• Methyl 2-Octynoate

Special cases

Butylphenyl methylpropional
It is a moderate sensitizer, but it is suspected of being an endocrine disruptor and was deemed not safe enough by the SCCS (European Scientific Committee on Consumer Safety), which recommends its ban in cosmetics.

Evernia prunastri / Evernia furfuracea
These tree mosses can contain chloroatranol and atranol, which are also considered “of high concern” by the SCCS, and that are now prohibited.

Hydroxyisohexyl 3-cyclohexene carboxaldehyde
As it was deemed too allergenic by the same expert Committee, it was too banned for use in cosmetic products.

The other cosmetic allergens

However, beware: it is not enough to be able to recognize the 26 “official” allergens to avoid all those that can be found in cosmetic products. Indeed, there are many, many other substances whose sensitizing potential can be just as strong as those first targeted by regulations.

In 2012, an SCCS evaluation concluded that consumers were ill-informed of the presence of perfume allergens in cosmetics and recommended applying the labelling obligation to more than 80 others of them, including chemicals and plant extracts.
In December 2018, the European Commission launched an impact assessment to analyse at least three options:
• Option 1: no labelling of additional fragrance allergens
• Option 2: labelling additional fragrance allergens according to the present rules of the Cosmetics Regulation, i.e. on the package of a cosmetic product or in other alternative ways (leaflets, tags, etc.)
• Option 3: e-labelling, through a website address, a QR Code or barcodes provided on the package
Further consultation phases are already planned before a decision is taken…

In addition, apart from perfumes, other cosmetic ingredients can prove to be sensitizers, sometimes strong ones. For example, the allergenic potential of Methylisothiazolinone, a preservative used in particular to replace parabens, was already known, but recently potentiated by its resurgence in many products. This led the European Commission to introduce strict restrictions on its use.

Of course, this is not enough to eradicate all risks of allergy – definitely not. And if it is true in many fields, it is even more so to say that in terms of exposure to sensitizing cosmetic ingredients, zero risk simply does not exist.
An indisputable fact that has resulted in the considerably more restrictive conditions for using the Hypoallergenic claim, applicable since July 1, 2019.

© 2016- 2021  CosmeticOBS

Associated elements(8)

Ingredient of the monthOther articles