Each year, the American Contact Dermatitis Society (ACDS) names an allergen of the year with the purpose of promoting greater awareness of a key allergen and its impact on patients. Often, the allergen of the year is an emerging allergen that may represent an underrecognized or novel cause of allergic contact dermatitis (ACD). In 2019, the ACDS chose parabens as the “nonallergen” of the year to draw attention to their low rate of associated ACD despite high public interest in limiting exposure to parabens.1
What types of products contain parabens?
Parabens are preservatives commonly found in many different categories of personal care products. Preservatives inhibit microbial growth and are necessary ingredients in water-based products. The 4 most common parabens used in personal care products are methylparaben, ethylparaben, propylparaben, and butylparaben.1 Parabens are metabolized to 4-hydroxybenzoic acid and are excreted in urine. When parabens are applied topically, there is minimal penetration through intact human skin.2 In the United States, parabens are allowed as preservatives in cosmetics at concentrations up to 0.4% when used alone or up to 0.8% when used in combination with other parabens.3
Consumers are exposed to parabens in a wide variety of personal care products. The Contact Allergen Management Program (CAMP) is a system owned and managed by the ACDS that typically is used to generate lists of safe personal care products for patients and also can be queried for the presence of individual chemicals in products. According to a 2018 query of the CAMP, parabens were found in 19% of all products.1 A more recent query of CAMP (http://www.contactderm.org/resources/acds-camp) in March 2019 showed parabens were present in 39.3% of makeup products, especially in eye products, foundations, and concealers; parabens also were found in 34% of moisturizers, 11.5% of soaps, and 19% of sunscreens. Notably, 14.8% of prescription topical steroids listed in the CAMP contained a paraben. Another method for evaluating chemical contents of personal care products is a review of the Voluntary Cosmetic Registration Program, a US Food and Drug Administration–based registry for cosmetic products. Survey data from the Voluntary Cosmetic Registration Program in 2018 documented methylparaben in 11,626 formulations.4 Other parabens included propylparaben (8885 products), butylparaben (3915 products), and ethylparaben (3860 products). Parabens were reported more frequently in leave-on rather than rinse-off products.4
In medications, parabens are recommended at concentrations of no more than 0.1%.1 Fransway et al1 compiled a list of medications that contain parabens, including commonly prescribed dermatologic topical medications such as corticosteroids, several acne preparations, eflornithine, fluorouracil, hydroquinone, imiquimod, urea, and sertaconazole. Oral and parenteral medications including local anesthetics and corticosteroids also may contain parabens.
Consumers also may be exposed to parabens through foodstuffs. Methylparaben and propylparaben have been classified as generally recognized as safe in foods by the US Food and Drug Administration.5 The acceptable daily intake of parabens in food is 0 to 10 mg/kg of body weight,1 and the estimated dietary intake for a typical adult is 307 mg/kg of body weight daily.6 Several studies on paraben content in foodstuffs have confirmed their presence in both natural and processed foods.1,6 Systemic contact dermatitis caused by ingestion of parabens is rare. In general, individuals with positive patch test reactions to parabens should not routinely avoid them in foods or oral medications,1 but they should, of course, be avoided in topical medications.