Fast Five Quiz: Idiopathic Pulmonary Fibrosis Differential Diagnosis

Guy W. Soo Hoo, MD, MPH; Zab Mosenifar, MD


January 26, 2023

It is important to distinguish IPF from fHP because these two conditions have different treatment and outcomes. HRCT imaging of patients with fHP typically demonstrate predominant patchy ground-glass or nodular opacities in a bronchovascular distribution and evidence of expiratory air trapping, whereas patients with IPF demonstrate lower lobe fibrotic changes. In patients with interstitial fibrosis, findings of extensive bilateral ground-glass opacity favor the diagnosis of NSIP, CHP, or desquamative interstitial pneumonia over IPF.

Another important characteristic that distinguishes fHP from IPF is its association with a potential provocative agent. FHP occurs when susceptible individuals develop a delayed fulminant autoimmune response to an inhaled antigen: dust, viruses, bacteria, plants, and fungus. Long-term inflammation leads to fibrosis, mimicking symptoms of IPF.

Consolidation in patients with IPF may suggest overlapping infection or malignancy.

Learn more about the differential diagnosis of CHP.


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