Which specific environmental exposures should I inquire about when assessing a patient for hypersensitivity pneumonitis?

When assessing a patient for hypersensitivity pneumonitis (HP), it is essential to inquire about specific environmental exposures that are known triggers. These include exposure to bird proteins (such as from pigeons, parrots, or other pet birds), moldy hay or straw (farmer’s lung), exposure to mold or fungi in damp environments, and occupational exposures such as those encountered in farming, bird handling, woodworking, and exposure to metalworking fluids. Additionally, exposure to humidifiers, air conditioners, or hot tubs contaminated with thermophilic actinomycetes or other microbes should be explored. It is also important to ask about exposure to certain chemicals or dusts in workplaces, including those in plastic manufacturing, mushroom farming, and exposure to isocyanates or other industrial agents. A detailed history should cover both domestic and occupational environments to identify potential antigen sources that could provoke HP ¹ (Patel et al., 2001; Quirce et al., 2016; Ojanguren et al., 2020).