Allergic Contact Dermatitis to Herbicides

To the Editor.—  Since Spencer's original article in 1966¹ on herbicide dermatitis, little has been written on the sensitizing potentials of herbicides. Indeed, the exact incidence of contact dermatitis to herbicides remains unknown.During the past 24 months, we have patch-tested 22 patients suspected of having herbicide-induced allergic contact dermatitis. They were tested for all or part of a "herbicides tray" consisting of ten herbicides. These herbicides were all of 1% concentration (commercial source) in petrolatum and were applied for 24 hours. The patch tests were then read at 24, 48, and often at 72 hours after application. The herbicides selected for administration were these: amiben, atrazine, Bladex, Dyfonate, Furadan, Lasso, Lorox, Ramrod, 2-4-D Weed Killer, and Treflan. All patients had a history of exposure to one or more herbicides.

Results.—  The only positive or irritant reactions occurred with Ramrod and Lasso, plus one questionable reaction to Treflan at