Modulation of the immediate allergic wheal reaction in the skin by drugs inhibiting the effects of leukotriene C4 and prostaglandin D2.

OBJECTIVE

To study the effect of nordihydroguaiaretic acid (NDGA), zafirlukast and indomethacin on the size of the size of the allergic prick-test wheal.

METHOD: In the first part of the study, NDGA and indomethacin, as well as the mepyramine control (10 micrograms/ml and 100 micrograms/ml), were injected intracutaneously 10 min before prick-testing with the cow dander allergen in 51 sensitised atopic subjects. In the second part, five other subjects were prick-tested with several allergens followed by administration of 40 mg zafirlukast or 100 mg indomethacin and re-prick-testing 2 h or 4 h later.

RESULTS

The intracutaneous indomethacin at both concentrations enlarged the wheal by 27 +/- 50% and 29 +/- 51% (P < 0.02, n = 51), respectively. Likewise, the peroral indomethacin significantly increased the wheal area by 17 +/- 30% (P = 0.035, n = 5). Neither intracutaneous NDGA in 51 subjects nor peroral zafirlukast in 5 subjects had marked effects on the size of the prick-test wheal. As expected, mepyramine (10 micrograms/ml) decreased the wheal area by 33 +/- 32% (P < 0.001, n = 51), but 14 subjects did not show any decrease after administration of this H1-antihistamine.

CONCLUSION

The prostaglandin synthesis inhibitor (indomethacin) augments the prick-test wheal, but the leukotriene synthesis inhibitor (NDGA) and leukotriene C4 antagonist (zafirlukast) have no marked effects on the size of the prick-test wheal.