Acrylate allergy typically is the result of sensitization to the acrylate monomers. In theory, gel nail acrylate materials are polymerized following exposure to a light-emitting diode or UVA lamp; however, there likely is some incomplete polymerization, which can increase the risk for development of allergy. Allergen exposure can occur due to incorrect application of the light source; inadvertent monomer exposure, which occurs when nail technicians wipe extra acrylate off of a client’s finger(s); or inadvertent application of acrylate monomers to objects in the nail technician’s work environment.6,8
Several acrylate nail allergens have been reported. Many studies have identified 2-hydroxyethyl methacrylate (HEMA) as the most common nail acrylate allergen.8,9 At least one study identified 2-hydroxypropyl methacrylate as the most common, with HEMA in second place.6 Other reported acrylate allergens have included ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, methyl methacrylate, ethyl cyanoacrylate, 1,4-butanediol diacrylate, hydroxypropyl acrylate, and 2-hydroxyethyl acrylate.8,9
The American Contact Dermatitis Society Core Allergen Series and the North American Contact Dermatitis Group screening series currently include HEMA, methyl methacrylate, ethyl acrylate, ethyl cyanoacrylate, and TSFR.4,10 Of note, acrylates are not included in the thin-layer rapid use epicutaneous (T.R.U.E.) patch test (SmartPractice), so they will be missed if this series is used.11 In the setting of suspected nail acrylate allergy, some authors recommend initial screening with HEMA and ethyl cyanoacrylate, with extended acrylate testing if both are negative.8
Upon patch testing with an acrylate series, patients frequently react to 2 or more acrylates and the reactions can be strong (++) or extreme (+++), which may represent cosensitization or cross-sensitization.8 The likelihood of cross-reactivity between acrylates is not clear, though it has been postulated that it is theoretically possible.6
An important pearl for patch testers using the chamber method is proper storage of acrylate allergens and assembly of trays prior to patch testing. Similar to all haptens, manufacturers recommend that acrylates should be stored in a refrigerator, but some authors suggest that acrylates should be stored in the freezer.12 Acrylates are volatile chemicals and rapidly degrade when exposed to air. A methyl methacrylate preparation loaded into an inert quadrate (IQ) chamber and stored at room temperature showed a nearly undetectable amount of any residual methyl methacrylate 24 hours later. Refrigeration of allergens in chambers slowed but did not stop eventual degradation, with nearly all acrylate preparations reaching an undetectable level of allergen by day 8.13 Acrylates, along with other volatile allergens, should only be loaded into chambers immediately prior to placement on the patient.
Allergy Prevention
Prevention of nail acrylate allergy among consumers is simple: avoid contact with the offending allergen. Acrylate spillover (ie, applying the acrylate onto the skin) and direct contact with objects and working surfaces contaminated with acrylate-based nail products should be avoided.8 Avoidance is more complicated for nail technicians, but it is thought that nitrile gloves allow for the best dexterity and allergen avoidance when acrylate exposure is brief.14 Allowable exposure times with nitrile gloves may be 15 to 30 minutes. After this times passes, a glove change is required to avoid exposure.14 Wearing nitrile gloves for longer than 15 to 30 minutes will result in cutaneous exposure and risk for dermatitis in sensitized patients. If longer wear is desired, one option includes cutting the fingertips off of Silver Shield/4H gloves (Honeywell Safety Products USA, Inc), applying them to the distal fingers, and wearing a standard nitrile glove over top, known as the finger stall technique.6 In one study, this technique was recommended to nail technicians with acrylate allergy. A telephone survey conducted 4 to 43 months later confirmed that 36% (8/22) of participants were using the technique without symptoms. In this same study, 73% (16/22) had continued working as nail technicians.6
Acrylates are used for other medical purposes, including dental procedures, orthopedic procedures, surgical glues, wound dressings, and contact and intraocular lenses. They also have additional cosmetic applications, including eyelash and hair extensions.8 Therefore, it is vital that patients disclose any history of acrylate allergy to both their medical and cosmetic providers.
Our Final Interpretation
Acrylate allergy has become increasingly common, and long-lasting nail treatments often are the culprit. Whether through gels, dips, or shellac, repeated exposure to acrylates through nail treatments can increase the risk for allergy. The T.R.U.E. test alone will not make the diagnosis, as acrylates are not present in this patch test system. It is important to remind your allergic patients that acrylates are present in other compounds used for medical and cosmetic purposes. Avoidance is key, and for allergic patients who love to bedazzle their nails, we suggest less-permanent, acrylate-free nail polishes as alternatives.