Allergen-controlled study of intranasal immunotherapy for ragweed hay fever

Abstract 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 μg (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