Conditions associated with organizing pneumonia:
(1) pneumonia (bacterial, viral, etc)
(2) diffuse alveolar damage (organizing phase)
(3) radiation to the lungs
(4) aspiration pneumonia
(5) toxic pneumonia
(6) fume inhalation
(7) connective tissue disease (rheumatoid arthritis, Wegener’s etc)
(8) extrinsic allergic alveolitis
(9) pulmonary eosinophilia
(10) drug reaction
(11) organ transplantation
(12) inflammatory bowel disease
(13) adjacent to a neoplasm
(14) bronchial obstruction
If no cause is found then the case is designated cryptogenic.