Effects of high doses of topical steroids on both ragweed and histamine-induced nasal provocation.

Patients with ragweed-induced seasonal allergic rhinitis were assigned randomly to be challenged intranasally either with ragweed or histamine while asymptomatic before the ragweed season. After initial challenge, all were treated either by placebo (P), beclomethasone dipropionate (BE), 400 micrograms daily, or budesonide (BU), 1200 micrograms daily, intranasally for 14 days. Repeat challenge was then compared with the previous ones in order to assess the effects of both usual (400 micrograms) and high doses (1200 micrograms) of topical steroids on both allergen-induced and nonspecific (histamine) nasal reactivity. Incremental doses of either histamine or ragweed were insufflated intranasally until a positive response defined the threshold reactivity. Reactions were assessed by a combination of changes in flow rates (rhinomanometry), secretions (mL), and sneezes with ten minutes of challenge. There was no difference in initial threshold reactivities among the treatment groups. Neither BE nor BU changed reactivity to ragweed. There were no adverse reactions except epistaxis in two BU patients. Histamine challenges disclosed a change in threshold reactivity, BU (P much less than .01) greater than BE (P much less than .05), compared with placebo. In summary, even high doses (1200 micrograms) of topical steroids had minimal effects on the early response to intranasal ragweed challenge. In contrast, both usual and high doses affected nonspecific histamine reactivity; this may contribute to some of the clinical improvement noted in symptoms of allergic rhinitis.