In 2017, consumers spent an average of $8.53 billion on nail services.1 This booming industry is set to grow to more than $15.5 billion by 2024.2 Nail polishes and other nail cosmetic trends can present new exposures for consumers, including chemicals that can elicit allergic contact dermatitis. In this article, we discuss new nail trends and their associated allergens, the acrylates.
Traditionally, the most widely recognized nail polish allergen has been tosylamide/formaldehyde resin (TSFR). However, there now are many touted TSFR-free nail polishes on the market, and the rate of positive reactions to this chemical has been declining in recent years. The North American Contact Dermatitis Group reported a positive reaction rate of 1.3% from 2005 through 2006,3 and rates decreased to 0.9% from 2015 through 2016.4 An Australian study demonstrated a similar reduction in positive reaction rates to nail polish chemicals, with only 0.7% of patients reacting to TSFR from 2014 to 2016 and 0% in 2017. It is theorized that this reduction occurred from replacing TSFR in traditional nail polishes with other chemicals such as polyester resins and cellulose acetate butyrate.5
Acrylate-Based Nail Treatments
Consumers recently have been gravitating toward acrylate-based nail treatments vs traditional nail polishes for a variety of reasons. Often referred to as gels, dips, or shellac, acrylate-based nail treatments represent a hot new trend in nail cosmetics. These manicures are resistant to chipping and scratches, creating a like-new look that lasts for weeks after application. The long-lasting nature of acrylate-based nail polishes has made them wildly popular with consumers.
Traditional acrylic nails consist of a powder polymer mixed with a liquid monomer, which polymerizes when a catalyst is added.6 The procedure is time consuming and can take up to 2 hours for application. In contrast, the newer gel manicure can be completed faster and includes application of acrylate-based nail polish, including a base coat, 2 coats of color, and a top coat. Exposure to either a light-emitting diode (30–60 seconds) or UVA (2 minutes) lamp is necessary after each coat is applied for polymerization (Figure 1).6 This long-lasting, semipermanent manicure typically is what patients are referring to when they say they have “gel nails.”
Gel dipping powders (referred to as dips) are another long-lasting acrylate-based nail treatment. This type of polish uses ethyl cyanoacrylate, a slightly different acrylate (yes, that IS super glue). After the nail is prepared, a base polish is applied to three-quarters of the nail and it is dipped into a natural color dip powder. The base polish is then applied to the entire nail, followed by a dip into the polish color of choice. This process is completed twice, followed by shaping and application of a top coat (Figure 2).
Finally, there are nail wraps, which are similar to stickers placed over or extending the nail plate. The wraps can be made from linen, silk, vinyl, or other material. Ethyl cyanoacrylate and isopropyl-2-cyanoacrylates have been identified in nail wrap adhesive.7 The heated product is directly applied to the prepared nail, and the excess wrap is filed off. Additional nail polish and a top coat usually are applied to finish the nail. Many of these products are available for in-salon use as well as online purchase and home application by consumers.
Patients who are allergic to acrylates can present with different patterns of dermatitis. Although the majority of patients present with dermatitis on the hands, fingers, or wrists, up to 10% may only have facial and neck dermatitis.8 Less commonly, the abdomen and thighs can be involved.6,8 Nail technicians most commonly present with pulpitis with cutaneous fissures.8 Other symptoms can include subungual hyperkeratosis, onycholysis, and nail dystrophy. Paresthesia, urticaria, and upper respiratory tract symptoms can occur but are less common.6,8