Cosmetics and Allergies
C onsidering their widespread use, adverse reactions to cosmetic ingredients only occur in a minority of individuals. But the allergies are still a problem so knowing what the causes are and how to screen your patients for them is important. Under certain circumstances, cosmetics can cause either irritant or allergic contact dermatitis. Photoallergic and contact urticarial reactions have also been described. Cosmetic companies have made an effort to exclude allergens in their products to avoid consumer complaints. Some have even labeled their products “hypoallergenic,” but the Cosmetic, Toiletry and Fragrance Association states, “the term hypoallergenic is a marketing claim.” There are no real federal guidelines for supporting this claim. Fragrances are the most common cause of cosmetic allergies, while preservatives rank second. The majority of reactions to fragrance are due to its inclusion in personal skin or haircare products rather than perfume or cologne itself. Screening for Fragrance Allergies Screening with two substances, Balsam of Peru and fragrance mix, helps to identify the majority of patients with fragrance allergies. Balsam of Peru is a natural product derived from fir trees that grow in San Salvador. Many of the allergens of fragrances are either ingredients of Balsam of Peru or chemically related. However, this allergen will only detect about half of the fragrances your patients are sensitive to, so it’s necessary to also test with the fragrance mix. This patch test mixture contains eight common fragrance allergens: • oak moss absolute • cinnamic aldehyde • cinnamic alcohol • alpha amyl cinnamic alcohol • geraniol • hydroxycitronellal • isoeugenol • eugenol. The North American Contact Dermatitis Group’s most recent survey found that fragrance mix was the second most frequent allergen with a reactivity rate of 14.0%. Only nickel sulfate, with a 14.3% reactivity rate, gave more positive reactions. This recent study revealed that fragrance mix co-reacted with 86% of positive reactions to fragrance ingredients and is, therefore, the most useful screening allergen for fragrance allergy. Irritant contact dermatitis, photo contact, contact urticaria, and pigmented contact dermatitis to fragrances have also been reported. Compared to allergic contact dermatitis, photo allergic contact dermatitis from fragrances is uncommon. Only musk ambrette has caused a significant amount of photosensitivity and has been removed from perfumes and colognes in the United States. The management of fragrance allergies includes the use of “fragrance-free products.” But it’s important to note that unscented products contain a masking fragrance that may not be suitable for some patients. Certain flavors and spices, such as cinnamic aldehyde alcohol, vanilla and eugenol, present in toothpaste, baked goods, chewing gum, etc., may also cause local or systemic symptoms when ingested by fragrance allergic individuals. Preservative Allergies Preservatives are the second most common cause of cosmetic allergy, but must be included in skincare products because of the harsh penalties that are imposed if these cosmetics become contaminated on the shelf. Some of the most commonly used preservatives are the formaldehyde-releasing preservatives. In fact, quaternium 15 is the most common cause of cosmetic preservative allergy in the United States. There are four other formaldehyde-releasing preservatives — DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, and 2-bromo-2nitropropane-1, 3-diol. These preservatives have in common the characteristic that there is an easily detachable formaldehyde component contained in the structure of the molecule, which can be released into the product in small amounts. Patients may cross react to formaldehyde and cross react to other formaldehyde-releasing preservatives, or they may be individually allergic to the preservatives. There are two other newer preservative systems that are important. The first is methyl chloroisothiazolinone/ methyl isothiazolinone, sold under the trade name of Kathon CG. This preservative is used in skin care products such as moisturizers, shampoos and make-up. For example, it’s the preservative in Eucerin cream and lotion. Another preservative system, introduced in the United States in 1990, is methyldibromoglutaronitrile/phenoxyethenol sold under the trade name of Euxyl K-400. A number of cosmetic manufacturers had begun to use this preservative as an alternative because of its weak sensitizing capacity in animal experiments. Unfortunately, as use of this preservative has increased, the rate of sensitivity has increased, and the recent North American Group’s data found a 1.5% incidence of reactivity. Some of the Lubriderm products use this preservative. Salon Product Problem Haircare products are the third most common cause of cosmetic contact allergy after fragrance and preservatives. The most common cause of contact allergy to hair coloring products is paraphenylenediamine. This is, of course, an important occupational problem for hairdressers, and can be disabling. Paraphenylenediamine also causes allergy in their clients and in a significant number of men and women who dye their hair themselves. This presents a major problem because it’s the only permanent hair dye available. Some patients with hair dye allergy use henna, which imparts a reddish color to the hair, or temporary coloring agents, which wash out after several shampoos. Acid or hot permanent waves, which have been used in salons in the United States for the past 30 years, create a long-lasting curl in the hair and contain glycerylthiogoycolate. These permanent wave solutions were first reported to cause contact allergy in 1984 and have since been a problem, particularly for hairdressers, but also for clients. A rather recent cause of contact allergy in shampoos and cleansers is cocamidopropyl betaine. Because of its quality of not burning or stinging the eyes, this has replaced other surfactants in shampoos. The impurities contained in the manufacture of the commercial products may, in fact, be responsible for allergy to cocamindopropyl betaine. It’s thought that amido amine is the contaminant, which is responsible for the majority of allergy to cocamidopropyl betaine. Nail products are another cause of cosmetic allergy. In recent years, sculptured artificial acrylic nails have become increasingly popular and fashionable. These artificial nail systems usually use an acrylate such as Krazy glue or other acrylates, which are very strong sensitizers. In 1974, the FDA banned the use of methyl methacrylate in artificial nails because of severe contact dermatitis, paronychia and nail dystrophy. However, other acrylates are used and cause problems on the fingertips, and also in areas that the hands touch, such as the eyelids, face and neck, mimicking a nail-polish dermatitis. Testing Importance Although cosmetics are relatively safe in terms of the rates of reactivity, searching for the causative agents in cosmetics can sometimes be difficult, but is important and can be accomplished through comprehensive patch testing.
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