To verify of cetirizine dry syrup to ketotifen dry syrup in the change of total nasal symptom score (TNSS) over the total treatment period from the score of the baseline assessment period

Inclusion Criteria:

• Children with perennial allergic rhinitis.
• Giving informed consent.
• Children with a positive response to specific IgE antibody test.
• Children assessed as positive in the nasal eosinophil count.
• Children whose severity score of nasal symptom is 4 or higher.

Exclusion criteria:

• have spastic disease such as epilepsy
• have a history of drug hypersensitivity
• are pregnant, lactating or possibly pregnant female Children
• are sensitive to pollen as a duplicate allergen and whose treatment periods are thought in the pollen dispersion periods
• have vasomotor rhinitis and eosinophilic rhinitis
• have asthma that requires the treatment with corticosteroid
• have inappropriate complication of nasal disorder that may influence on the evaluation of the study drugs
• have complicated with atopic dermatitis or urticaria that requires the treatment with antihistamine preparation
• have started specific desensitization treatment or nonspecific modulation treatment but who have not reached the maintenance level of treatment
• have received surgical treatment for reduction and modulation of nasal mucosa
• redintegration therapy of nasal cavity to improve the degree of nasal airway
• surgical operation to improve rhinorrhea.