Evaluation of Efficacy and Safety of Levocetirizine to Subjects With Perennial Allergic Rhinitis to House Dust Mites

Inclusion Criteria: * male or female ≥ 12 years * suffering from a perennial allergic rhinitis to house dust mites for at least 2 years * positive skin test or positive Radio-Allergo-Sorbent-Test for house dust mites * the mean of the T4SS evaluated in the evening over the last 24 hours of the selection period was ≥ 5 Exclusion Criteria: * seasonal allergic rhinitis likely to change significantly the symptoms of the subject * an ear, nose or throat (ENT) infection during the two weeks preceding initial visit * asthma requiring corticosteroid treatment * atopic dermatitis or urticaria requiring an antihistamine treatment or the administration of oral or topical corticosteroids * associated ENT disease