Bullous Dermatitis in Field Workers Associated With Exposure to Mayweed

Abstract

Fourteen cases of bullous contact dermatitis were identified among 42 members of a field crew pulling weeds in a field of sugar beets near Willows, CA in May 1989. The grower's pesticide application records showed that no pesticides had been applied to the field since November 1988 and no pesticides were present on tested samples of sugar beet foliage. The principal weed identified in a botanical survey of the field was Mayweed (Anthemis cotula), but other species were also noted, including cocklebur (one of several Xanthium species), and prickly lettuce (Lactuca scariola). Experimental patch testing with A cotula in a volunteer subject demonstrated its capacity to produce skin irritation. Irritant reactions to A cotula were felt to be the probable cause of the observed outbreak of contact dermatitis in the fieldworkers.