Usual interstitial pneumopathy in a patient with hypersensitivity pneumonitis and microscopic polyangiitis. Case report.

One of the most frequent diffuse interstitial lung diseases is hypersensitivity pneumonitis. It is related to exposure to diverse antigens, causing fibrosis in advanced stages, making the differential diagnosis with interstitial pulmonary fibrosis difficult as it overlaps with the usual interstitial pneumonia pattern. On the other hand, there are interstitial lung diseases associated with ANCA, such as microscopic polyangiitis, which is also related to the usual interstitial pneumonia pattern.