Updated Imaging Classification of Hypersensitivity Pneumonitis

Abstract

Hypersensitivity pneumonia (HP) refers to a heterogeneous group of interstitial lung diseases resulting from a non-IgE immune-mediated reaction to inhaled pathogens in susceptible and sensitized hosts. Environmental and genetic factors are important substrates of disease pathogenesis. A recurrent or ongoing airborne exposure results in activation of humoral and cellular immune responses. This article discusses key clinical, radiologic, and histopathologic features of HP and reviews current recommendations.

Keywords: Fibrotic hypersensitivity pneumonitis; high-resolution CT; histopathology; interstitial lung disease; non-fibrotic hypersensitivity pneumonitis.