Abstract
Hypersensitivity pneumonitis (HP) is a disease triggered mostly by organic particulate matters in genetically susceptible individuals. Environmental exposure is usually complex and comprises not only offending antigen but also cigarette smoke, common dust, mycotoxins and air pollutants.
The disease has heterogenous clinical presentation based on the interaction of individual host factors and components of inducing matter. The complex underlying pathogenetic mechanisms associated to HP contribute to the vast interindividual variation in clinical presentation of the disease.
Chronic HP has unfavourable prognosis and can successfully mimick idiopathic pulmonary fibrosis. Aside avoidance of exposure, and corticosteroids in acute HP, there is currently no evidence- based treatment in HP.
New treatment targets should be identified based on revelation of critical pathogenetic steps.