Skin Hypersensitivity Reactions to Preservatives

Preservatives are chemicals that are added to products that contain an aqueous phase. These include cosmetics, topical medications, household products, foods, and industrial products such as glues, paints, dyes, metalworking fluids, and spin finishes. They are biocidal or biostatic, inhibiting the overgrowth of micro-organisms and protecting and retarding the chemical degradation of the product. The ideal preservative should be an effective antimicrobial that is stable, non-toxic, nonirritant and non-sensitising. No one preservative fulfils these ideal criteria and all preservatives are known to cause contact allergy. In cosmetics, preservatives are second only to fragrances as the commonest cause of allergic contact dermatitis. We present a case of allergic contact dermatitis to methyldibromo glutaronitrile (MDBGN) in a worker employed in an industry that manufactures polypropylene fibres from plastic polymers.