Interstitial lung disease or post COVID-19 lung disease: A complex pulmonary differential

In the four years since the start of the COVID-19 pandemic, a large number of affected individuals including survivors of severe SARS-CoV-2 infection continue to experience symptoms ranging from mild breathlessness to persistent respiratory disability. Whilst the pneumonic complications of COVID-19 particularly those encountered in the early waves are widely recognised, post-COVID interstitial lung disease (ILD) remains a poorly understood and contentious entity. In clinical practice, distinguishing pre-existing ILD that has been aggravated by COVID-19 from a persisting pulmonary disease that can be confidently attributed to the viral infection remains challenging. The auto-inflammatory nature of COVID-19, the radiologic manifestation of particular ILD patterns and the truly progressive clinical characteristics in a minority of post-COVID-19 sufferers all add to the diagnostic and management complexities of this entity.