Modern concepts of clinical variants and features of hypersensitivity pneumonitis in children

Abstract

Hypersensitivity pneumonitis (HP) (J67) is the most common interstitial lung disease in children and adolescents. The disease is immunologically determined, it can be a disease when exposed to various factors that cause harmful effects on the environment. The most significant are thermophilic actinomycetes, antigens of animal and fungal origin. Currently, cases of “two cases of infection” have been identified, when a genetic predisposition has been identified in case of detection of cases of antigen results in the implementation of diseases. Immunological studies in GP are mainly focused on identifying specific IgG to the “guilty” antigen. High-resolution computed tomography is the most sensitive method of visualizing the GP, pathological changes are detected in more than 90% of patients. According to the characteristics of the clinical course and duration of the disease, acute (lasting less than 6 months) and chronic (more than 6 months) variants of the disease are distinguished. The formation of fibrosis of the lung tissue up to the honeycomb lung is observed in approximately 18% of cases. There are variants of HP: with fibrous and non-fibrous (inflammatory) phenotype. The basis of drug therapy so far is systemic and inhaled glucocorticosteroids, the use of which is pathogenetically substantiated and clinically effective. The prospects for therapy are also associated with the use of antifibrotic drugs: pirfenidone and nintedanib, which slow down the decline in lung function and improve patient survival. At the same time, the exclusion of contact with a causally significant allergen plays a key role. Our own observations concern 280 children with GP aged 8 months to 16 years, including 70 patients in the first year of life. Most patients had a hereditary allergic burden (in 74%) and a causal factor was traced. The prognosis, with rare exceptions, was favorable. The main reasons for poor outcomes in GP are continued contact with a causally significant allergen, late diagnosis of the disease, and inadequate therapy.