FC04.3 Allergy to phthalic anhydride/trimellitic anhydride/glycols copolymer in nail varnishes

Abstract

Introduction: Nail varnishes are well‐known sensitizers, and the most frequent allergen is nowadays tosylamide/formaldehyde resin (TFR). We present 3 cases of allergic contact dermatitis (ACD) due an unusual ingredient.Case reports: The 1st patient presented with atopic dermatitis that progressively worsened, involving face and neck for several months. The 2nd patient had history of occupational allergy to glutaraldehyde, and presented with head and neck dermatitis. The 3rd patient had severe onycholysis and dermatitis of perionychium, face, neck and décolleté. European standard series was negative in all patients, as was TFR, (meth‐) acrylates and cosmetic series when tested. Patch tests with patient’s own varnish(es) were ++, and breakdown identified phthalic anhydride/trimellitic anhydride/glycols copolymer (PTG) as the allergen (tested 1 to 5% pet.).Discussion: PTG results of condensation of phthalic anhydride, trimellitic anhydride, ethylene glycol, and neopentyl glycol monomers. It belongs to the copolymer class, and is used in confection of nail polish and enamels, like TFR or phthalic anhydride/glycerine/glycidyl decanoate copolymer. Our patients had long lasting dermatitis, common in ACD to nail varnishes. Sensitivity was proved by patch testing with patient’s own cosmetics. Allergic contact dermatitis to PTG seems to be rare, but has to be considered particularly in patients with negative standard patch tests. An alternative is the use of tosylamide/formaldehyde‐based nail polish.