Asthma due to insecticide sensitivity.

Two patients are reported in whom asthma was precipitated by exposure to synthetic organophosphorous insecticides. Investigation showed no evidence of systemic poisoning or cholinesterase inhibition and indicated that the asthmatic reactions may have been due to a sensitivity response. The mechanism of this response is unknown but it was inhibited by corticosteroids in one patient. A history of insecticide exposure was obtained from the affected patients only after careful questioning and indicates the need for awareness that sensitivity to insecticides may precipitate asthma and that little exposure is necessary to elicit a response.