Heat treatment of Japanese lacquerware renders it hypoallergenic

Japanese lacquer is made from the sap of the Japanese lacquer tree (Toxicodendron vernicifluum),a member of the Anacardiacae plant family.Objects painted with this material are described collectively as lacquerware.Both fresh lacqure and lacquerware may evoke allergic contact reaction sacribable to the urushiols contained therein.In this study,we have examined the effects of heating on the abiility of lacqerware to elicit an allergic contact reaction.Lacquer films perared with and without heat treatment were tested on urushiol-sensitive subjects.Patch test reactions were strongest to unteated film and decreased with increasing level of heat treatment.Assays for free urushiol in the lacquer films demonstrated that free urushiol content decreased with increasing heat treatment and that urushiol with saturated and monounsaturated alk(en)yl chains predominated.