During this conference, a three-lecture session was about the allergies to cosmetics. Current regulation, new allergens, management of patients, or management of the specific cases of hair cares or sunscreens creams: an occasion to learn more about troubles that draw more and more patients to meet dermatologists.
First part: Regulation and management
The European Regulation on cosmetics makes it mandatory to put on the labels the
list of ingredients
, with their
names, in descending concentration's order.
The allergic patient and his (her) M.D. shall learn to read in " INCI language ", and it is not always that easy … Underneath, some examples of this INCI language:
• Plants often come with their Latin name: Myroxilon Pereirae is the Peru balsam.
• The names of chemical ingredients are often almost incomprehensible: for instance, Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde is nothing other than Lyral (an allergen recently added to the 2009 European Standard battery of tests).
• Water comes as Aqua (while it is listed as Water in the CTFA nomenclature, which is applicable in the USA) …
Further, reading the list of ingredients once is not enough: the manufacturers may modify the formula (sometimes while keeping the same name and the same packaging), and the list of ingredients may be modified. To play it safe, better to read again the list before buying a product, even if one has used it for a long time.
The "well-known" allergens
are still at the top of the list of the contact allergens in cosmetics.
As per the current regulation, it is mandatory to put in the list of ingredients twenty-six substances considered as potentially allergenic and used as fragrances or aromatic additives, as soon as they are at 0.01% minimum in a rinse-off product and at 0.001% minimum in a leave-on product. In INCI nomenclature, a fragrance may appear as "Fragrance" or "Aroma", which comprises all the substances of the aromatic compound, the twenty-six allergens and the others … However, if a manufacturer uses an essential oil that naturally contains one of these substances, both shall appear in the list of ingredients (for instance, Lemon Essential Oil and Limonene ).
A peculiarity: Benzyl Alcohol is among the twenty-six odorous substances that shall be listed , but it may be used as a preservative and found in a "fragrance-free" product.
The new European Standard Battery of Tests (ESB)
Among the 26 aromatic allergens , only eight are detected by the allergy tests of the current European Standard Battery, known as Fragrance Mix. A new test, Fragrance Mix II (including six other substances from the list of 26) is added in the 2009 Standard Battery.
• Kathon CG® (Methylisothiazolinone + Methylchloroisothiazolinone ) is a very common allergen. Its prevalence is decreasing, except for the wipes for babies; as it is a leave-on product, the substance stays in contact with the skin.
• MDGN (Methyldibromo Glutaronitrile) is a strong allergen. It is now completely banned in cosmetics, and, then, should no longer be a problem. Nevertheless, it has been added in the standard battery.
• Allergies to Formol and to Formol releasers are on the rise.
• Parabens are never, or almost never, considered as the cause of allergies. For allergists, there are risk-free. However, allergists and toxicologists have often different opinions on this point.
Other preservatives , such as the Dimethylglutaronitrile, sometimes put forward as an alternative to Parabens , come with some drawbacks of their own. Essential oils may also be used as preservatives , but they also may be allergenic .
The new allergens
Further to these well-known allergens, fragrances and preservatives , nowadays many more are marketed … More products that are "natural" means more ingredients, and ingredients more widely used than previously. This leads to new allergies, for instance, to the essential oils , Chamomile, Aloe vera …
There are also many new ingredients in cosmetic products ; that means as many new potential allergens.
Hydroxydecyl Ubiquinone (or Idebenone)
This anti-oxidant, a member of the Quinones family, a synthetic copy of the Coenzyme Q 10, contained in an anti-ageing care, is the cause of two acute contact eczema, which have been reported in papers.
• Copolymers (PVP and derivatives). They are widely used in make-up (lips, eyes) and in sunscreens. They are film-forming , adhesive, antistatic and stabilizing. The sensitizing properties of these large molecules have been underestimated for a long-time. They are the cause of contact allergies, regularly described since several years. Among the 200 copolymers used, only 7 are recorded as allergenic .
• Alkylglucosides . They are produced by the reaction of a fatty alcohol with glucose or with a glucose polymer. They have been used in the industry and in cosmetics as mild non-ionic surfactants in rinse-off products (shampoos, soaps, hair colorants); they are used more and more now in leave-on products (lotions, creams, sunscreens). Thus, there are more and more allergic reactions. There are also crossed-reactions between several alkylglucosides: Cetearyl-, Coco-, Decyl- and Lauryl Glucoside, the latter being the most powerful allergen.
• DMAPA (Dimethylaminopropylamine) . It is used to synthesize the alkylamidobetaines surfactants , and may be found as an impurity in some batches of Coco-Betaine, Cocamide MEA, Cocamidopropyl Betaine, Oleamidopropyl Dimethylamine. As it is not considered as an ingredient per se, DMAPA is not INCI registered and may not be specified on the labels. People who are allergic to it have no choice other than avoiding all the alkylamidobetaines.
• Proteins derivatives. Sesame, corn, oats, Hydrolyzed Wheat Proteins …are well known for the on-the-spot reactions they give. Some contact eczema has been reported recently. These ingredients shall be monitored, especially in people developing atopic reactions.
Allergic people management
How to give advice and warnings in case of contact allergy to cosmetics? Dermatologists have access to:
• Lists of products to avoid for the best known allergens (lists of products containing these allergens, then, that shall be avoided)
• Standard batteries of tests depending on the job (hairdresser, dentist …)
• A positive list of suitable cosmetic products
Patients are always required to report the dermatologist any contact allergy. The dermatologist may then report to the Cosmetovigilance Network, and to the manufacturer, which may consider it for a further modification of its formula.
Second part: Allergies to shampoos and hair cares
The main hair products that cause contact sensitization are well known. Underneath, a list that classifies them in order of frequency:
1. Colorants and discolouration agents
2. Shampoos and conditioners
3. Gels, foams and restructuring products
Occasional or frequent, temporary or permanent, it involves almost 50% of the women worldwide. Contact allergies to hair colorants are more and more frequent, probably due to this rising use. Of all the people who use hair colorants, 5.3% have an eczema or an oedema reaction to a hair colouring. However, among hair professionals, the number of allergic reactions to hair colorants dwindles.
BEWARE! A new kind of allergy is reported more and more: an acute reaction, giving an immediate oedema very similar to a Quincke oedema. Indeed, it is a very quick reaction, which, nevertheless, is of the same kind as a delayed allergy. This phenomenon is quite new, as, until very recently the reactions were always delayed, in the form of eczema and itching on the scalp and on the auricular sulcus, sometimes going to the face, the neck and the shoulders.
The allergens of hair colorants
These products are always listed:
• Para-PhenyleneDiamine (PPD) and its derivatives. Note that PPD is used in henna tattoos, to darken them; this may give birth to impressive allergies on the drawing of the “tattoo”. Some products sold by "natural brands" may contain PPD …
• Toluene-2,5-Diamine (PTD)
Nevertheless, other colourants, such as the azoic dyes, may be a cause for sensitization, including through another way: clothes, as they are used also in dyes for textile.
Rheology modifiers, anti-oxidants or surfactants are also recorded as allergens. On the other hand, discolouration agents (Ammonium Persulfate) and perm products (Glycerylmonothioglycolate) are rarely at the root of intolerance reactions.
Allergies to shampoos
When faced to eczema, not only on the scalp, but also on the face, especially on the forehead and the temples, an allergy to a shampoo is the first idea that comes to mind. Among the strong allergens they may contain, of course,
, but also more and more detergents and
are suspected to give these reactions.
The amphoteric surfactants are the first to be fingered out [Cocamidopropyl Betaine and its allergen, the Diaminopropylamine or 3-Dimethylaminopropylamine (DMPA) has been known for more than 20 years], but the non-ionic surfactants (glucosides), quite often an alternative to Cocamidopropyl Betaine, may also be considered.
Tests on hair products
The standard battery comprises PPD, Fragrance 1 and 2, Peru balsam,
, Isothiazolinone, Methylglutaronitrile … The battery specific to hair comprises in addition PTD and aminophenols …
Nevertheless, it is on the safe side to test systematically the personal products. More and more, indeed, sensitizations may be due to substances that are not in these batteries. The personal product shall be applied after a check of the pH. The reading is generally carried out after 48 and 96 hours, but a delayed reading is recommended to be sure not to have missed a delayed reaction.
Third part: Allergies to sunscreen's creams
A sunscreen is not a cosmetic product as the others. In the USA, it is even classified as a medicine.
Sunscreen's creams are used more and more, thanks to the campaigns in favour of protection against the sunrays to prevent cutaneous ageing and photo-inducted cancers. At the same time, the frequency of the allergic reactions to their use is probably underestimated.
The active agents of sunscreen's creams
The anti-UV protection comes from different kinds of substances:
An organic screen,
a very mild allergen as the
Tinosorb M, which makes a kind of mesh of very large molecules on the surface of the skin, with a broad spectrum of absorption (280 to 400 nm). Its
name comes as Methylene Bis-Benzotriazolyl Tetramethylbutylphenol.
• A mineral screen, non- allergenic , such as the Titanium Dioxide or the Zinc oxide (ZnO). Note that the micronization of mineral screens makes them less visible, less white on the skin. When as nanomaterials , they are even less visible. Nevertheless, the fate of these nanomaterials and their potentially toxic effect are still debated.
• A chemical filter. Chemical anti-UV filters are, by definition, photo reactive (light alters them). They may be allergenic and photosensitizing . Some of them may be used to stabilize others.
Photo allergies are difficult to detect. During the tests, it is necessary to expose the sunscreen brought by the patient under UVA radiation (in specific booths) to prevent false-negatives.
The allergy is generally direct, though it could occur by proxy (through a contact with the person who applied the sunscreen cream). Some allergies come only as acute and intense oedema.
The excipient of sunscreen's creams, as for all the other cosmetics, may be also at the origin of the contact eczema. It may be the fragrance , preservatives , surfactants , or more specific agents as the film-forming , which increase the resistance to water, such as the PVP eicosene copolymer, for which some cases of allergy have been reported.
The progression of allergies to sunscreen's creams
Allergies to sunscreens have come as "epidemic periods" since they were marketed. In order of emergence:
Used since 1947, it is mainly an anti UVB filter. It causes allergies, especially crossed-allergies with some dyes for clothes or with PPD. Note that PABA
will be banned in cosmetics
on 8 October 2009, after a European Directive issued on 18 December 2008.
• Benzophenone-3 (Oxybenzone). Used since the ‘70s, Benzophenone-3 is efficient against UVB as well as against the short UVA. It causes immediate and delayed allergies and a crossed-allergy with Ketoprofen. It is widely used to protect textiles, paints, rubber against UV radiation.
• Iopropyldibenzoylmethane . Available since 1985. It is a strong allergen and photo allergen.
• Octocrylene (OC). Available since 2003 and close to the cinnamates family, more and more used in the last 10 years, until recently it was considered as well tolerated. However, since the last year, a series of photo allergies in which it may be involved to have been reported. Is it a new epidemic? An interesting point, not yet understood, a photo allergy to octocrylene is very frequently found in patients who have had previously an allergy to Ketoprofen (KP). Several assumptions are made to explain this double allergy. However that may be, it is essential to advise against the using of sunscreen's creams with OC to photo protect people who have a history of photo allergy to KP.
Keep in mind that sunscreens are also used in cosmetics other than sunscreen's creams, such as anti-ageing products, lipsticks, hair protection, and even textiles, which may be another source of contact dermatitis. "Questioning-like" and tests with the products that the patient uses are the keys for the right diagnosis by the dermatologist.
Dr Marie-Pierre Hill-Sylvestre© CosmeticOBS-L'Observatoire des Cosmétiques