• Thirteen costus-sensitive patients were patch tested with 38 sesquiterpene lactones of five different classes over a two-year period. Cross-reacting agents fell into two chemical categories: (1) those that resembled the primary sensitizer, and (2) those belonging to different skeletal classes. An exocyclic methylene group conjugated to a γ-lactone was present in both chemicals that cross-reacted and those that did not. The difference between these two groups is that cross-reacting chemicals are not highly substituted, tending to be lipophilic, while those giving negative responses all are highly substituted at the C-8/C-6 position. This functional group may hinder binding of exocyclic methylene with skin protein or the actual antigenic site with an immune receptor cell.
(Arch Dermatol 116:59-60, 1980)
Epstein WL, Reynolds GW, Rodriguez E. Sesquiterpene Lactone DermatitisCross-Sensitivity in Costus-Sensitized Patients. Arch Dermatol. 1980;116(1):59-60. doi:10.1001/archderm.1980.01640250061017