Undisclosed methyldibromo glutaronitrile causing allergic contact dermatitis in a NSAID cream.

The allergenicity of methyldibromo glutaronitrile (MD BGN) (1,2-dibromo-2,4-dicyanobutane) is well recognized, both in occupational and in non-occupational settings (1). Used as a preservative, alone or in combination with phenoxyethanol (Euxyl K 400), in metalworking fluids, cosmetics, adhesives, and moist toilet tissues, it was identified as an increasingly important allergen soon after its launch in the 1980s (2, 3). The increasing rates of sensitization to this preservative prompted the European Commission to restrict its use, first in leave-on (4), and later also in rinse-off cosmetics (5). Despite these recommendations, which have shown to be successful in reducing the prevalence of contact allergy to this molecule (3), some important consumer products, such as topical drugs, are still not subject to regulatory intervention. We report two cases of allergic contact dermatitis caused by MDBGN in a topical non-steroidal antiinflammatory cream.