Local nasal immunotherapy for Dermatophagoides-induced rhinitis: efficacy of a powder extract

Local nasal immunotherapy by means of an extract in "macronized" powder from was studied in allergic rhinitis to Dermatophagoides species.

Twenty-four Dermatophagoides-sensitive patients were studied for 12 months in a double-blind controlled trial. Subjects were selected on the basis of a positive history, skin test, radioallergosorbent test, and intranasal challenge to Dermatophagoides antigen. Two 12-patient groups were selected at random; the first group was given active treatment, and the second received placebo.

After 6 months, the mean weekly symptom and medication scores were significantly lower in the treated group than in the control group. The treated group had a significant increase of specific nasal threshold to Dermatophagoides antigen after treatment. Adverse reactions to local nasal immunotherapy, which were limited to the upper respiratory tract, occurred very rarely and did not interfere with dose schedule.

Local nasal immunotherapy in powder form may be a suitable alternative to the traditional subcutaneous immunotherapy in terms of clinical efficacy and safety.