An international working group report in AJRCCM, published on 1 October 2026, updates the 2016 definition of acute exacerbation of idiopathic pulmonary fibrosis and extends it to all fibrotic interstitial lung diseases.
The revised definition is an acute respiratory event with increased symptoms or signs and imaging or histology consistent with diffuse alveolar damage, with or without organising pneumonia, in a patient with known or newly diagnosed fibrotic ILD. Alongside it, the group proposes 'acute respiratory worsening' for deteriorations not due to diffuse alveolar damage — heart failure, bronchitis or pneumonia — while noting that severe pneumonia can itself trigger an exacerbation.
No treatment is proven for acute exacerbation, and mortality remains high. The practical value is a shared structure for evaluating an acute deterioration and for separating treatable causes from true exacerbation.
- In acute deterioration of fibrotic ILD, look for new ground-glass change on CT consistent with diffuse alveolar damage.
- Exclude heart failure, infection and pulmonary embolism, which fall under acute respiratory worsening.
- Apply the same framework to non-IPF fibrotic ILD, not only IPF.
- Discuss prognosis and goals of care early, given high mortality and no proven therapy.
Why it matters
A common definition across fibrotic ILDs makes both bedside assessment and trials more consistent.
Don't overread it
A consensus framework, not new treatment evidence.
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