Pyrethrum: An etiologic factor in vasomotor rhinitis and asthma

Abstract

Sufficient data have been presented to indicate the divergence of opinion in regard to the various properties of pyrethrum. It is evident that many problems of a definite nature still remain to be solved. A thorough consideration of the literature, therefore, in addition to my own personal experience evidenced by the series of cases herein reported, leads to the following summarization: It is questionable whether the particular substance (or substances) in which the insecticidal principle or principles is believed to reside is responsible, in whole or in part, for the symptoms of vasomotor rhinitis, asthma, or anaphylatic dermatitis exhibited by some individuals who come in contact with pyrethrum. It is pointed out by McCord and his coworkers that other substances in pyrethrum having no known insecticidal value are recognized as local irritants; that, in addition to the essential principles, pyrethrum camphor (C 10H 16O), pelletorin, essential oils, an alkaloid, inulin, tannin and other factors have also been found to be present. Resinous substances, they state, were found in certain samples of pyrethrum flowers, in as high percentage as 13.76, the yield of alcohol-ether extraction being as much as 30.47 per cent. These resins, oils, camphors, etc., they believe are irritants contributing to the etiology of the skin lesions observed by them. While the opinion expressed by these writers in connection with the skin eruption no doubt applies in some instances, other factors, I believe, may contribute in other subjects. The effect of pyrethrum evidenced by a dermatitis, I agree, may in some nonsensitive individuals be due to a local irritating action; in others, however, it probably is the result of a specific hypersensitiveness. The more remote manifestations contributing to vasomotor rhinitis and asthma, I believe, may in some persons also be due to irritant reactions following actual contact, but they more probably are the result of reactions of a true immunologic nature in an atopic individual who is specifically hypersensitive to the pollen of pyrethrum.