The aim of this study is to investigate the short and long term efficacy and the safety of SCRT treatment for PAR

Inclusion Criteria:

1. age 18-60 years
2. presence of two or more nasal symptoms (rhinorrhea, nasal congestion, nasal itching and sneezing) with severity score ≥ 2 (0 = no symptom, 1 = mild symptom, 2 = moderate symptom, and 3=severe symptom)
3. presence of nasal symptoms more than 2 consecutive years; and
4. positive reaction to the one or more perennial allergen in skin prick test.

Exclusion Criteria:

1. treatment with nasal/oral corticosteroids within the past month; nasal cromolyn or tricyclic antidepressants within the past two weeks; or nasal/oral decongestants, nasal/oral antihistamines, or antileukotrienes within the past week
2. presence of rhinosinusitis (paranasal sinus X-ray demonstrating mucosal thickening, or partial or complete opacification of the paranasal sinuses)
3. presence of hypertension (systolic ≥ 180 mmHg or diastolic ≥ 100 mmHg)
4. presence of abnormal liver function (aspartate transaminase (AST) or alanine transaminase (ALT) ≥ 100 IU/L) or abnormal renal function (blood urea nitrogen (BUN) ≥ 30 mg/dL or creatinine ≥ 1.8 mg/dL (male), 1.5 mg/dL (female))
5. presence of neoplasm, severe systemic inflammation, other systemic disease that affects rhinitis
6. history of drug allergy
7. history of anaphylaxis for allergic tests
8. pregnancy or lactation
9. participation of other clinical study within the past 3 months.