The aim of the study is to assess the effect of specific immunotherapy (SIT) to dust mites on clinical symptoms, reliever drugs usage, inhaled glucocorticosteroid usage, quality of life, lung function, bronchial hyperreactivity with methacholine, and presence and type of allergy after three years of SIT in children with asthma.

According to Global Initiative for Asthma treatment of asthma is based on avoidance of allergens, pharmacological treatment, and specific immunotherapy.

The aim of the study is to assess the effect of specific immunotherapy (SIT) to dust mites on clinical symptoms, reliever drugs usage, inhaled glucocorticosteroid usage, quality of life, lung function, bronchial hyperreactivity with methacholine, and presence and type of allergy after three years of SIT in children with asthma.

Inclusion Criteria:

• patients allergic to house dust mites
• patients with moderate bronchial asthma
• patients with controlled asthma
• patients who were qualified for immunotherapy and gave written informed consent for immunotherapy (active treatment group)
• patients who were qualified for immunotherapy and did not agree with this kind of treatment - did not give written informed consent for immunotherapy (control group)

Exclusion Criteria:

• patients allergic for other perennial and seasonal allergens
• patients with other chronic diseases 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
• medications that resulted in patient exclusion included:anti-parasites or oral corticosteroids within 6 months before the first visit.