Allergen-controlled study of intranasal immunotherapy for ragweed hay fever.

Previous studies of intranasal immunotherapy have not included control groups treated with an irrelevant allergen. In the present double-blind study, we tested the effectiveness of intranasal immunotherapy in 20 patients sensitive to both short ragweed (SRW) and orchard grass (OG). Patients sprayed increasing concentrations of either SRW (n = 11) or OG (n = 9) extract intranasally six times per day for 8 wk before the SRW pollination season. The effects of this treatment were determined by analysis of symptom score diaries and clinical examinations during the SRW pollination season. SRW-treated patients received cumulative AgE doses from 3 to 59 micrograms (mean 21); this mean dose was approximately sevenfold less than that used in a previous study from our laboratory. All patients reported immediate hay fever symptoms after use of the nasal spray. Five patients (four SRW- and one OG-treated) reported episodes of mild epistaxis during treatment; no other unexpected side effects were noted. During the treatment period, more SRW-treated patients showed signs of nasal obstruction and edematous nasal mucosa than OG-treated control patients (p less than 0.03). During the SRW pollination season, the SRW-treated patients reported lower mean weekly symptom scores than the OG-treated control patients, but the difference was not statistically significant. Supplemental antihistamine use was significantly higher (p less than 0.016) in the OG-treated control patients during the SRW pollination period. Subjective assessment of treatment efficacy by patients was similar in both treatment groups. We conclude that intranasal immunotherapy was of only marginal benefit in this study.