Last reviewed 08/2021

As its name implies most cases are idiopathic, occuring in previously healthy individuals with no identifiable cause. It has however been described following recovery from a viral or mycoplasma pneumonia and has been reported as occuring in association with other diseases.

The occurrence of cryptogenic organizing pneumonia has been reported with connective tissue disorders such as rheumatoid arthritis, polymyositis and Sjogren's syndrome. Cases are also reported following the administration of certain drugs and following bone marrow and lung transplantation. Numerous related disorders include human immunodificiency virus infection, radiotherapy, thyroiditis and alcoholic cirrhosis.