The purpose of the trial is to compare the efficacy and safety of sublingual seasonal and annual immunotherapy in children with allergic rhinitis allergic to grass pollens.

Allergen immunotherapy is currently the only one method of cause treatment of the IgE-dependent allergic diseases. Sublingual immunotherapy (SLIT) is the method which allows to give allergens via alternative oral route in patients home. Due to the possibility of avoiding injection this therapy allows to have better relationship with patient, and reduce the costs of therapy thanks to reducing the numbers of visits in out-patient clinic.However efficacy and safety of sublingual immunotherapy are still important issues, especially in children.

The purpose of trial is to compare the efficacy and safety of sublingual seasonal and annual immunotherapy in children with allergic rhinitis allergic to grass pollens.

Inclusion Criteria:

• Children with seasonal allergic rhinitis, allergic to grass pollens, first diagnosed at least 2 years before inclusion into the study

Exclusion Criteria:

• Active upper respiratory tract infection within 3 weeks before the study and acute sinus disease requiring antibiotic treatment within 1 month before the study
• Allergic rhinitis hospitalisation during the 3 months before the first visit.
• Additional criteria were other clinically significant pulmonary, hematologic, hepatic, gastrointestinal, renal, endocrine, neurologic, cardiovascular, and/or psychiatric diseases or malignancy that either put the patient at risk when participating in the study or could influence the results of the study or the patient's ability to participate in the study as judged by the investigator.
• Excluded medications were systemic corticosteroids.
• Patients who were receiving immunotherapy were also excluded.