A Comparative Study of the Clinical Efficacy of Immunotherapy and Conventional Pharmacological Treatment for Patients with Perennial Allergic Rhinitis

Abstract

This study was designed to compare the clinical outcome of prolonged immunotherapy for perennial allergic rhinitis with that of pharmacological treatment. Patients with perennial allergic rhinitis due to Dermatophagoides farinae ( D. farinae ) were divided into two groups; a pharmacotherapy group and an immunotherapy group. The pharmacotherapy group was treated with conventional pharmacological treatment using antihistamine tablets and topical steroid sprays and the immunotherapy group was treated with D. farinae extracts for 5 successive years. None of symptom scores at enrolment differed significantly between the groups. At 6 months and 1 year after the start of treatment the rate of decrease in each score was significantly greater in the pharmacotherapy group than in the immunotherapy group. The rate of decrease in sneezing scores, but not in the other scores, at 2 years after the start of treatment was also greater in the pharmacotherapy group than in the immunotherapy group. However, at 3 years the rate of decrease in any of the scores did not differ significantly between groups. The differences between the groups became clear-cut again after 5 years of treatment, when the rate of decrease in all of the scores was significantly greater in the immunotherapy group than in the pharmacotherapy group. Therefore, short-term treatment with pharmacological agents is probably superior to immunotherapy but, in the long-term, immunotherapy is apparently superior to pharmacological treatment with respect to clinical efficacy. In addition, prolonged immunotherapy provided long-term clinical efficacy and might provide a long-standing cure even after discontinuation of the therapy. In a questionnaire interview, approximately half of patients were very satisfied with prolonged immunotherapy, and three-quarters were fairly satisfied or more. Additionally, the magnitude of improvement in nasal stuffiness contributed significantly and exclusively to the patient evaluation of immunotherapy. We propose that prolonged immunotherapy is never inferior to anti-allergenic pharmacological treatment and that it is possible to achieve long-term clinical efficacy or long-standing cure even after the discontinuation of immunotherapy, and that patients with perennial allergic rhinitis will be very satisfied with this prolonged therapeutic technique if nasal stuffiness is considerably alleviated.