Every two years, the North American Contact Dermatitis Group collects and reports the data from patch testing among its members to a standardized series of allergens.
There are 3 categories of cosmetic ingredients that induce allergies more often than others:
Fragrances are the most frequent allergens, but specific allergen avoidance is complicated by the fact that manufacturers are not required to disclose the exact fragrance ingredients in products. Also, when a product lists essential oils, patients may not recognize this as fragrance.
Another important cause of contact dermatitis caused by cosmetics is the variety of preservatives added to the cosmetic products to prevent bacterial and fungal contamination. There are a number of preservatives used in cosmetics that can cause eczema in the sensitive consumer. For example, formaldehyde releasers.
• Hair colorants & agents for permanent waves
Other important causes of contact allergy include the active agents in hair- and nail-care products such as those for permanent hair waves, perma- nent hair coloring, artificial nails, and nail polishes.
NACDG* List of Most Frequent Allergens
- Balsam of Peru – Fragrance antibacterial antifunga
- Fragrance mix – Fragrance
- Thimerosal – Preservative
- Formaldehyde – Preservative
- Quaternium-15 – Preservative
- p-Phenylenediamine – Hair Dye
- p-Aminobenzoic acid – Sunscreen (PABA)
- 2-Bromo-2-nitropropane-1 3-diol – Preservative
- Imidazolidinyl urea – Preservative
- Lanolin alcohol – Emolliant Stabiliser
- Glyceryl thioglycolate – Perming solution
Fragrance is the most common cause of contact allergy caused by cosmetics according to the North American Contact Dermatitis Group (NACDG)
1998–2000 patch-test results. Fragrances can be naturally derived from plants or synthesized in laboratories. Although >5000 different fragrance chemicals are known, it is possible to identify up to
95% of fragrance allergic patients by testing the following 11 substances: cinnamic aldehyde, cinnamic alcohol, geraniol, eugenol, isoeugenol, oak moss absolute, alpha-amyl cinnamic alcohol, sandalwood oil, hydroxycitronellal, narcissus absolute, and ylang-ylang oil.
After a fragrance allergy is once established, the patient should avoid indefinitely all products that contain fragrances. If somebody is sensitive to only a single or a few fragrances, avoidance of those particular fragrances may allow the successful use of others. But again, because of the fact that fragrances are not required for package labeling, it is essentially impossible to knowledgeably avoid a particular fragrance.
Balsam of Peru
Balsam of Peru is a natural mixture of aromatic chemicals produced from a tree in Central America (Myroxylon pereirae). It has a pleasant odor from cinnamein, cinnamic acid and vanillin. Besides its use as fragrance it is also used as antibacterial, antifungal, and antiscabetic agent. Balsam of Peru
contains also other allergens, such as benzoic acid, benzyl acetate, cinnamic alcohol, coniferyl alcohol, eugenol, cinnamic aldehyde, and methylcinnamate. Interestingly, patients sensitive to balsam of Peru have been found to be also allergic to certain spices, oranges, chocolate, Coca-Cola, cinnamon, and vermouth.
Little has been reported about allergic reactions to botanicals. However, with the current popularity of botanicals in cosmetics, more reports will surely be seen. In the dermatological literature cases with allergic dermatitis have been reported with aloe vera, arnica, Asiatic pennywort, lavender, tea tree, peppermint, cucumber, rosemary, sage, stinging nettle tea, chamomile tea, and witch hazel. Although many people think that allergies are primarily related to synthetic ingredients, allergic reactions can also occur with any natural ingredient independent on its processing (e.g. plant extracts, essential oils, herbal powders).
Several sunscreen agents on the market are capable of producing contact dermatitis. In the past, paraaminobenzoic acid (PABA), was the most common sensitizer. As a result, PABA is currently used in only few sunscreen products. Today, oxy- benzone (benzophenone-3) is the most commonly reported sunscreen sensitizer with 0.6% of persons reacting. Avobenzone is a less frequent cause of allergic reactions. Derivatives of PABA, benzophenones, cinnamates, and dibenzoyl- methanes can all cause photo-allergic dermatitis (allergy that occurs only upon sun exposure).
Allergens in Hair Care Products
The active agents in hair care products, including hair colorants and permanent waves, are the third most common source of allergic reactions to cos- metic products. One of the most common allergen is paraphenylenediamine (PPD), a chemical used
for permanent hair colorants. Up to 5% of all women show allergic reactions to PPD. Once the hair colorant is fully developed, PPD is no longer an allergen. Therefore, patients sensitive to PPD will recover from their allergies once PPD is oxidized and do not need to cut their hair. The agents used in permanent waves are also an important cause
of dermatitis. Glyceryl thioglycolate is found in acid (heat) permanent waves used exclusively by salons and can cause allergies in 2.0% of test persons. Ammonium thioglycolate is the chemical in alkaline permanent wave products intended for home use and can also cause dermatitis. Patients who react to glyceryl thioglycolate permanent solutions can typically tolerate ammonium thioglycolate-based perms and vice versa.
Marks JG, et al. American J Contact Dermat 2003; 14: 59
Ortiz KJ, et al. Dermatologic Therapy 2004;17:264