Management of fibrotic hypersensitivity pneumonitis

Purpose of review Recent guidelines have updated the classification of hypersensitivity pneumonitis, stratifying by the presence or absence of fibrosis as either fibrotic or nonfibrotic hypersensitivity pneumonitis. Fibrotic hypersensitivity pneumonitis represents up to 10% of interstitial lung disease in large cohort studies, and is occasionally even more common in some regions; however, there are many unknown aspects to the diagnosis and management. The goal of this review article is to summarize the management of fibrotic hypersensitivity pneumonitis. Recent findings Historically, the only treatment options for patients with hypersensitivity pneumonitis were antigen avoidance and corticosteroids, although other immunosuppressive therapies are increasingly endorsed by experts in the field. There is accumulating evidence that antifibrotic medications can be useful as a second-line therapy in some patients with fibrotic hypersensitivity pneumonitis who have progression despite immunosuppression. There remains no direct comparison of immunosuppressive vs. antifibrotic medication for the management of fibrotic hypersensitivity pneumonitis, but some clinical, radiological and pathological features may suggest greater likelihood of benefit from one option or the other. We anticipate that future treatment of fibrotic hypersensitivity pneumonitis will consider a variety of patient features to suggest the most prominent underlying biology that will then be used to guide initial pharmacotherapy; however, additional data are still needed.