ABSTRACT
BACKGROUND AND OBJECTIVES: Long-term immunotherapy lasting for 3 to 5 years is known to be one of the effective treatment modalities for the perennial allergic rhinitis. However, it is questionable whether open-ended immunotherapy is beneficial to control the symptoms of perennial allergic rhinitis. This study was designed to confirm the effectiveness of open-ended immunotherapy with every 3-month injection after 3-year immunotherapy by comparing the results of immunotherapy between patients who received less than 3 years and those who received more than 3 years. MATERIALS AND METHOD: One hundred-one perennial allergic rhinitis patients who received immunotherapy more than 1 year and had no history of sinonasal operation were chosen. They were divided into two groups; the duration of immunotherapy was from 1 year to 3 years in one group and more than 3 years in the other group. They were surveyed with global study and the questionnaires regarding practical problems about nasal, eye, and generalized systemic symptoms as well as their medical treatment history. This questionnaire was administered twice in one sitting, with the first on recalling symptoms before immunotherapy treatment, and the second on an evaluation of current symptoms. RESULTS: Improvement in the allergic symptoms was preserved in group B as well as in Group A. With the treatment, the patients in both groups experienced decrease in the frequency of absence from work or school, hospital visits and the use of antibiotics. There were no significant differences in the results between two groups. CONCLUSION: The long-term maintenance of immunotherapy with 3-month injection after 3-year immunotherapy is effective for the prevention of recurrence of perennial allergic rhinitis.