The purpose of this study is to evaluate the non-inferiority clinical efficacy of two different drug associations in the treatment of Moderate - Severe Persistent Allergic Rhinitis.

• double-blind, non-inferiority, prospective, parallel group trial.
• Experiment duration: 07 days.
• 02 visits (days 0 and 7).
• Efficacy will be evaluated for persistent allergic rhinitis based on nasal symptoms score
• Adverse events evaluation.

Inclusion Criteria:

• Consent of the patient or legal guardian;
• Clinical diagnosis of moderate - severe persistent allergic rhinitis according to the classification of ARIA (Allergic Rhinitis and Its Impact on Asthma);
• Children aged between 2 and 11 years and 11 months (up to 30 kg);
• Presence of nasal symptoms score greater than or equal to 5 (scale 0 to 12)in the last week;
• Evidence of sensitization to aeroallergens in examination (immediate skin tests or serum specific IgE) in the 12 months prior to inclusion.

Exclusion Criteria:

• Participation in clinical trial in 30 days prior to study entry;
• Patients receiving immunotherapy;
• Patients with history of hypersensitivity to desloratadine or prednisolone or with corticosteroids use contraindications ;
• Patients with any clinically significant disease other than allergic rhinitis, including hematopoietic, cardiovascular, renal, neurological, psychiatric or autoimmune disorders;
• Patients on treatment with monoamine oxidase inhibitors (MAOIs);
• Patients who were in use of oral antihistamines or decongestants in the past 15 days;
• Patients who were treated with systemic corticosteroids in the last month;
• Patients who have uncontrolled asthma, chronic sinusitis, drug related rhinitis and nasal anatomic abnormalities.