The children of school age, suffering from severe bronchial asthma, who live in the city often have the atopic variant of severe asthma, manifestations of the concomitant allergic pathology and drug allergy with not high level of nitric oxide in exhaled air. The children from rural areas have the mixed variant of severe bronchial asthma, as well as drug allergy and high level of nitric oxide in exhaled breath condensate.
