The presence of sulfites in ‘natural rubber latex’ and ‘synthetic’ rubber gloves: an experimental pilot study

Sulfites are widely used as antioxidants and preservatives (1-3), but are also frequent contact sensitizers. Indeed, more than 1% of subjects routinely patch-tested to sodium metabisulfite (SMB) 1% diluted in petrolatum (pet.), the best marker to detect contact allergy to sulfites (1), are sensitized to them (1, 4). SMB 1% pet., has recently been piloted in the European baseline series (5), but in spite of the high yield of positive patch-test reactions, clinical relevance remains difficult to establish in roughly half of the cases (1, 2, 4). When cosmetics, pharmaceuticals or food products are involved, the presence of sulfites needs to be labelled, however, when unlabelled product types are concerned, determination of the actual sulfite-containing allergen source(s) may prove challenging.