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8 alkyl gallates, including the widely used antioxidants propyl, octyl, and dodecyl (= lauryl) gallate, have been subjected to experimental sensitization in guinea pigs. Using a modern sensitization procedure, the results showed that all gallates are moderate to strong contact sensitizers: dodecyl (= lauryl) gallate was found to be the strongest. A characteristic correlation between side chain length and mean response was observed, giving a maximum of sensitization at a length of 12 carbon atoms (dodecyl gallate). A literature review revealed that the frequency of reports of allergic contact dermatitis from antioxidants of the gallate type has increased in the last 4 years. In most cases, the moderate sensitizer propyl gallate was the source of sensitization.

Additives are now an established part of our packaged food. Some, like colouring agents and flavouring compounds are hardly necessary or even redundant. Others, mainly antimicrobials and antioxidants, are very important. Antioxidants are not only added to food, but also to cosmetics, pharmaceuticals and industrial products. Dodecyl gallate belongs with propyl- and octyl-gallate to the synthetic esters of gallic acid. These lipid-soluble phenols are very effective antioxidants. We found contact allergy in 4 of 10 workers having only limited contact with dodecyl gallate in the very low concentration of 0.05%. It is important to recognize its strong sensitizing capacity. Workers working with dodecyl gallate should avoid direct skin contact.