Inclusion Criteria:  patients who have accomplished their per-protocol participation in trial NCT044155930. signed Informed Consent by parent/legal guardian and patient aged>16 years old patient's/caregiver's cooperation with researcher  Exclusion Criteria:  severe asthma uncontrolled mild/moderate asthma: forced expiratory volume at one second (FEV1)<80% (under 5 percentile), FEV1/forced vital capacity (FEV)<75% (under 5 percentile), hospitalization due to asthma exacerbation within last 12 months current oral/sublingual/subcutaneous immunotherapy with another allergen eosinophilic esophagitis allergic reaction of 4th or higher grade according to the World Allergy Organisation Systemic Allergic Reaction Grading System during immunotherapy a history of severe recurrent anaphylaxis episodes chronic diseases requiring continous treatment, including heart disease, epilepsy, metabolic disease, diabetes  medication:  oral, daily steroid therapy exceeding 1 month within the last 12 months at least two courses of oral steroid therapy (at least 7 days) within the last 12 months oral steroid therapy longer than 7 days within the last 3 months biological treatment the need to constantly take antihistamines therapy with b-blockers, angiotensin converting enzyme (ACE) inhibitors, calcium channel inhibitors pregnancy no consent to participate in the study lack of patient cooperation