Patch testing to plants: Some practical aspects of what has become an esoteric area of contact dermatitis

Patch testing to plants has become more difficult because previous sources of antigens are no longer available. Reagents for a few plants can be obtained from European suppliers. Others can be found in the standard test tray, on the kitchen shelf, and in stores marketing essential oils, but testing for some individual plants may necessitate using plants in the yard or extracts from them. There are problems inherent in the use of noncommercial materials. The methodology and some of the problems are briefly presented.