Introduction:
Hypersensitivity pneumonitis (HP) is one of the most common forms of interstitial lung disease in children. Due to its common association with occupational environment, it used to be considered an exclusively adult disease; however, hypersensitivity pneumonitis also affects the paediatric population, and is often associated with exposure to antigens in the home environment and with the pastime activities of children.

Objective:
The aim of the study is to present the current state of knowledge on hypersensitivity pneumonitis in children with a focus on the peculiarities of diagnostic investigation and management of the disease in this age group. The study includes a case report of the disease in a child.

State of knowledge:
In children, the most common factors causing HP are avian and fungal antigens present in the home environment. Diagnosis is based on the co-occurrence of characteristic clinical presentation, radiographic and pulmonary function tests findings, and a history of exposure to a potential triggering antigen. The main strategy in the management of HP is to eliminate the trigger factor with the use of a systemic corticosteroids therapy in severe or advanced cases.

Conclusions:
Due to the risk of irreversible changes in the respiratory tract, an early diagnosis is very important. A quick identification of the trigger factor and its elimination from the patient’s environment makes it possible to apply a less aggressive treatment, and to improve the patient’s prognosis. Unfortunately, due to its infrequent occurrence, hypersensitivity pneumonitis is often not taken into account in a differential diagnosis of respiratory diseases in children, which leads to a delayed diagnosis despite the characteristic clinical presentation of the disease.