Allergic sensitization of the skin and nails to acrylic plastic nails.

I RECENT months there has been made available plastic material which can be fashioned into artificial “finger-nails” that are advertised “for those who want long nails.” In addition, the plastic nails may be used by persons who wish to disguise dystrophic or diseased nails or who wish to discourage nail, biting. This plastic material is essentially the same as that used in acrylic dentures, and is marketed as a liquid monomer and powder polymer. The liquid monomer is methyl methacrylate, and the powder is polymethyl methacrylate. One manufacturer claims that the material is completely harmless. However, other manufacturers warn that allergic reactions to this material may be encountered. The acrylic liquid and powder used in artificial “nails” do not require heat for polymerization, but will polymerize and harden at room temperature. These selfcuring acrylic resins are created by inducing polymerization of the mixture of methyl methacrylate monomer and polymethyl methactylate powder with an organic peroxide and an accelerator or promoter. The self-cured resins are not quite as hard as those resins polymerized at high temperature, and they normally contain a somewhat higher residual monomer content than do the heat-cured resins. Nevertheless, these acrylic resins can be fashioned to form excellent plastic nails which remain intact for several weeks. In a previous communication, one of us (A.A.F.) pointed out that methyl methacrylate liquid monomer is a potent sensitizer and can cause allergic contact type of eczematous reactions on the skin and the oral mucosa, When the plastic acrylic “nails” became available, we predicted that allergic reactions to this material would occur. In a short time we were able to observe four cases of allergic eczematous contact reactions of the skin, onychial, and paronychial tissues due to acrylic plastic “nails.” Some of the reactions were rather severe and painful and caused nail changes which lasted for several months. In each case, we were able to prove that it was the liquid monomer that was the sensitizing agent. The powder polymer was inert, allergically speaking.