IGHE and hypersensitivity pneumonitis: Triggers of pneumonitis include a variety of airborne organic and inorganic irritants, as well as radiation therapy, aspiration and medications delivered by any route, resulting in non-IgE-mediated hypersensitivity pneumonitis (HP, also known as extrinsic allergic alveolitis), radiation-induced lung injury (RILI), and drug-induced interstitial lung disease (DILD), respectively.