Last month the Cooperative Extension
Service referred an allergist to the Agromedicine Program for consultation. His
patient, a 40-year old woman, claimed she was allergic to chemicals that drift from
an adjacent cotton field. She experiences headache, hives, and facial edema
following application. She said that her symptoms were seasonal and coincide
with the aerial pesticide applications. The patient presented two pesticide
labels, obtained from Clemson, to the physician and asked, “Are these farm
chemicals causing my allergy?”
The first label was for an
organophosphate plant growth regulator (ethephon) used to enhance boll opening
prior to harvest. The second label was for an organophosphate defoliant
(merphos) used to defoliate cotton plants at harvest. There is little
scientific evidence suggesting that either chemical is a human
sensitizer.
Dr. Schuman suggested that the physician consider
pyrethroid insecticides as a possible cause of the symptoms. Pyrethroids may
cause sensitivity in some patients, especially those with ragweed allergy. Several
pyrethroids are approved for use on cotton.
DEPARTMENT OF FAMILY MEDICINE – DIVISION OF PUBLIC HEALTH AND PUBLIC SERVICE
MEDICAL UNIVERSITY OF SOUTH CAROLINA, 171 ASHLEY AVENUE, CHARLESTON, SC 29425-2217