Inclusion Criteria:
* Ability to confirm voluntary participation and agreement with all study objectives by signing and dating the Informed Assent Form (IAF), with the participant's parent(s) or legal guardian(s) signing the Informed Consent Form (ICF);
* Age ≥ 6 years and \< 12 years on the date the IAF is signed and the ICF is signed by the parent(s) or legal guardian(s);
* Diagnosis of persistent allergic rhinitis (PAR) according to the Allergic Rhinitis and its Impact on Asthma (ARIA) criteria, with severe exacerbation;
* Evidence of sensitization to aeroallergens confirmed by a positive skin prick test and/or the presence of specific serum IgE;
* Nasal congestion severity score ≥ 2 points;
* Total Nasal Symptom Score (TNSS) ≥ 8 points.
Exclusion Criteria:
* Use of prednisolone or any other oral or parenteral corticosteroid within 7 days before enrollment;
* Use of topical or oral decongestants within 3 days before randomization;
* Participants receiving allergen immunotherapy;
* Participants with documented clinical evidence of significant acute or chronic sinusitis, in the opinion of the investigator, at the screening visit;
* Participants who have not responded to loratadine or desloratadine treatment;
* Use of antibiotics or an indication for antibiotic therapy at the screening visit;
* Use of desmopressin;
* Presence of adenoidal hypertrophy or known obstructive anatomical abnormalities (e.g., septal deviation) that may be responsible for nasal obstruction, in the opinion of the investigator;
* Diagnosis of other forms of rhinitis, including but not limited to idiopathic rhinitis (formerly referred to as vasomotor rhinitis), infectious rhinitis (including viral rhinitis), food-induced rhinitis, hormonal rhinitis, drug-induced rhinitis, atrophic rhinitis, or non-allergic eosinophilic rhinitis (NARES);
* Diagnosis of uncontrolled asthma;
* Use of inhaled corticosteroids for indications other than asthma maintenance therapy;
* History of seizures;
* Presence of systemic fungal infection;
* Presence of any uncontrolled infection;
* Any clinical finding (medical history, physical examination, or laboratory abnormality) that, in the investigator's opinion, may place the participant at risk or interfere with participation in the study, including uncontrolled chronic disease(s);
* Participants who are pregnant, breastfeeding, or post-menarche females of childbearing potential who are not using a reliable method of contraception;
* Known allergy or hypersensitivity to any component of the study medications;
* Current history of cancer and/or treatment for cancer within the previous 5 years;
* Participation in another clinical trial within the previous 12 months, unless the investigator determines that participation may provide a direct benefit to the participant.
