Contact sensitization by pesticides in farmers.

30 farmers with contact dermatitis and 20 controls were patch tested with a series of locally used pesticides. Allergic reactions to 1 or more pesticides were seen in 11 patients but none of the controls. Carbamates (maneb, carbofuran, carbaryl) were the most frequent sensitizers (7 patients), followed by organophosphorus compounds like: malathion and oxydemton methyl (4 patients); 2,4-dichlorophenoxyacetic acid and fenvalerate (3 patients each); streptocycline (2 patients). Irritant reactions to captaf were seen in 4 patients, thiobencarb weedicide in 3, and organophosphorus compounds in 3. Pesticides should be patch tested in all farmers with contact dermatitis.